Because it has a high price in the market so ofcourse people will use or invest in bitcoin if it is sky rocketing to a high price and also it is the first crptocurrency that is made so i guess bitcoin is already a thing and it is the first so other are just a copy of bitcoin.

It can overcome bitcoin in terms of trading volume but bitcoin is still going to be the most popular crypto currency. People/traders are just jumping from one coin to another if they can see that they will have good time to get some decent profit there. And that's why the market is slowly moving backwards and after a couple of days it's becoming green.

That is right, no other digital currency are more valuable than bitcoin. And also, bitcoin is so easy to earn so many people are making their way to earn and save them then sell it in the good time for a good profit.
I do the same, I save some for future use like investing in some ICOs and some things I want to buy. But what I like the most is that it can also increase it's price even if you just store it in your wallet.

Actually, in terms of trading volume, Ether did overtake Bitcoin a couple of months back. So some days Ether has more trading volume, some days Bitcoin has more trading volume. In terms of market cap, it will take some time.

http://www.trustnodes.com/2017/05/30/ethereums-trading-volumes-surpass-bitcoins-first-time

First Mover Advantage!

No other interesting coins around for a number of years.

The Mystery of Satoshi Nakamoto!

The story about that guy spending thousands of bitcoins for a pizza!

The wild swings in price attract attention.

Silk road and the whooo scaaaaary associations! Haha

The promise of bypassing banks, paypal, western union and the establishment for the first time!

The fragility of fiat currencies, and too much debt got many into it.

The limited amount of bitcoins. scarcity.

This adds up to a LOT of interesting DRAMA!

Bitcoin is the least boring thing in the whole world!

Is the potential fork not worrying anyone?

Actually come to think of it, what's the best wallet to be using when 1st Aug comes?

Bitcoin all started from scratch, from nil, from zero. All they've got was a great vision as well as ideas and principles from deep within. That fueled the first steps of bitcoin. Soon, after a few trusted the invention with all its peculiar features the world has not yet seen, it grew quite fast. The rest is history. Unlike so many other cryptos right now, bitcoin doesn't have a scammy past.

Bitcoin has been a great opportunities for everyone that has come across it,who has become miner and has earned from it. Bitcoin has been the first and the head of all the cryptocurrency which has ever existed. The main of its popularity has to do with the coins I.e currency attached, this will ever popularize BTC

I think that other altcoins are also important for bitcoin success, many people are involved in trading this days. How many exchange sites there is now, more then ever before for sure. Except that bitcoin created many rich people, others found a nice source of income, hobby for earning money from home like a side job, in today's times having money is a need, and all of us are looking for good source on income, bitcoin can provide that for us and with so many possibilities here we are entertained and wr earn thats why bitcoin is most popular cryptocurrency. After so many years, this year we saw legalization of bitcoin in several countries, that is one more reason why bitcoin is popular, everyone is talking about bitcoin.

bitcoin still popular mainly because first mover and natural growth.. alot of alts are just PnD controlled by a few of people especially POS coins