Concerning benefit attached to bitcoin investment still requires knowledge, loss is totally unpredictable meaning an investor might encounter loss while investing but what’s more important about bitcoin is your profit making will be determined by you alone (optional) bitcoin investment is a long term investment that requires a good plan so anyone who decides to go for short profit will see the end result probably loss. Meanwhile altcoins at the other hand is totally not safe, these coins are created by  group of people either a community yet what’s their aim exactly? No need for deep explanation most people ended up investing everything in a dump coin except they’re smart enough to identify a coin potential or else it’s risky, I believe we’ve talked more on bitcoin vs altcoin well it’s common.

Bitcoin has the largest market cap in the crypto market because it has the potential to store values and so much, not highily volatile like the AltCoins that're highily volatile very vulnerables to dump due to it limited utility potentials.
Very quickly, bitcoin has been a hot coin for enthusiasts in the crypto space in that it has a limited supply of 21 million invented bitcoins which is very intensive and attracted by users to buy because investors are holding and accumulating so much of it otherwise investing for long term which also big whales are diving into the bitcoin market including small investors are wailing to buy before it runs out of stock.
So it's like demands are more than the supplies due to the limited supply of bitcoin.

OP I think you should edit the title of your topic. I thought you were talking about the increase of members on the forum. It’s normal for people to become interested in bitcoin once the price is up, I think a lot of people are moved to buy bitcoin because of profits. And majority of them end up buying altcoins instead of investing in Bitcoin because they are interested in quick profits.

You’re right. You don’t need to buy 1 bitcoin($96k) at a time, buying a fraction of bitcoin using DCA strategy is the best way to accumulate bitcoins. I think the challenge is that most people buy bitcoin for investment purposes and have a preconceived notion that Bitcoin is a get-rich-quick scheme so you can imagine how buying $0.6 worth of bitcoin does not fit into their plan.

The answer to OP's question is very simple. People like winners and will do anything to be a part of the winning team. A lot of people who thought $50K bitcoin was expensive has since joined the bandwagon to ride it to $99K even at $100K and $150K, there would still be more buyers because Bitcoin is the only limited and finite asset in the world right now. So to conclude, use these on your bullet list of "why Bitcoin" question next time.

1. Only finite asset in the world (21M max supply, real number is even lower since millions is considered lost).
2. It's a movement already revolutionizing the financial world
3. Everyone loves winners and Bitcoin is one.
4. Permissionless and Completely community owned.
5. Bitcoin is Money. (this is the simplest definition of Bitcoin btw).

People have more confidence in bitcoin than any other altcoins out there, that's why the ownership of bitcoin keeps increasing everyday. Even when bitcoin dumps, it has the ability to get back to it's previous price and go far above it faster than any other altcoins out there. That's why people prefer it more than any other altcoins. Also it's decentralised nature is also one of the main reasons why it is the most preferred coin. Just look at what's happening in the market currently, bitcoin has crossed it's previous ATH months ago and has continued setting new ones, yet many of the altcoins are still struggling to get to half of their previous ATH. So there are many reasons to give your colleagues who are asking you why bitcoin is the most preferred when next they ask you such question. You don't even need to think about it or consult anyone before knowing what to say as regarding why bitcoin is the most preferred coin out there.

Bitcoin is freedom 
I would add up one more right here.

You yourself know that Bitcoin is the top number one coin in the crypto world and only Bitcoin has been declared as a legal currency in many countries. And on the other hand, Bitcoin's supply is limited and no one can increase its supply even if they want to. Due to which day by day the demand of Bitcoin will be more expensive. Investors have been investing in Bitcoin for years with this in mind. So the Bitcoin crisis is slowly appearing in the market and that is why Bitcoin is becoming more and more expansive. And in the future surely bitcoin will be more expansive everyone has to believe it.

Indeed, there are many reasons why Bitcoin is more popular than other crypto assets. The first reason Bitcoin has a decentralized system, in my opinion this reason is very interesting and a sign that differentiates Bitcoin from other crypto assets. Because most of the crypto assets or altcoins currently available, as far as I know, are not decentralized. So I personally think this is the factor that makes many people quicker to believe and invest in bitcoin. In essence, this decentralization factor makes people more confident and feel safe when investing in bitcoin.

The second reason is that bitcoin has a limited supply. This reason also has a big influence on the price of Bitcoin or the attractiveness of people to buy it. Because with a limited supply of bitcoin, the price will definitely get more expensive as time goes by. So it is not surprising that the growth of bitcoin investors is currently experiencing a very significant increase. This is different from the current Altcoins, most of which have a very large supply. So it is definitely very difficult for the price to increase significantly. I think in short that's why bitcoin is superior to other crypto assets.

The point is that investing in bitcoin is safer or has minimal risk and also has enormous potential than investing in other crypto assets.

Well, basically it is difficult to convince people why they should choose bitcoin, especially if they think that in altcoins they can get huge profits. These people usually only think about big and fast profits. For me personally, i will not try harder to explain to people who think like this, because people like this only need proof, and i will provide evidence of the results of my investment in bitcoin to them.