do not worry too much, what if you do not have much capital to buy both types of coins. just focus on what you believe. surely you know that bitcoin selling value is very high in altcoin appeal. should you buy bitcoin and save it until the price goes up.

if to buy bitcoin certainly quite expensive even though the price is currently down. but still expensive and cheaper for altcoin. and I guess depending as needed, if you are a trader or an investor. of course you will have bitcoin as an exchange tool.
I have bitcoin and of course some altcoin are still on hold. I think in the crypto world we have many choices

You can never have one strategy for all the market situation. Trading Bitcoin or altcoins or going for long term investment, is all dependent upon the market condition.

In Q1 of 2017, a long term (a year) hodl was profitable. In Q2, short term trade (1-2 months) was profitable. Q3 was good for shorting bitcoin and altcoins equally.  Q4 was amazing for short term trading for bitcoin and altcoins. Thus, having the same approach for trading and investing is never advisable. You need to change your strategy for maximizing the profit in the given market situation.

The Q1 of 2018, is so far good for day trading with the profit margin of 10%-50% or one can go long term investment that is for a year from the present price be it for Bitcoin or  altcoins. Right now, I am preferring Bitmex futures trading to short and long Bitcoins because of the high volatility in the present price.

For me I prefer to have this both but mostly I hold bitcoin and ethereum, most of my bitcoin is come from my altcoins bounty rewards that traded to become bitcoin and hold.
I hold some of my altcoins for long term that I believe has potential to pump someday.

In last pass year I realize that altcoin depend on bitcoin. If bitcoin price fall for 5% almost all altcoin will fall atleast 10%. That's why I don't really buy altcoin. I holding only bitcoin right now, mostly altcoin that I get from campaign I put on sale with x5 higher price and leave there , so maybe one day that coin went to the moon and spmeone buy it from me.

For now, I prefer altcoins because most of their price are very low and you can purchase much more tokens rather than bitcoin. But before I buy them, I make sure that their project is good and they are already listed on exchanges. However, I also have tokens from airdrops which doesn't have any values yet. I think airdrops are good for startups, you just need to promote the project and they will give some good number of coins and you just have to wait for it to be listed on exchanges so that you can start trading them.

Bitcoin still plays an important role, I disagree with what you say that bitcoin has a long-standing technology. You can see that bitcoin uses blockhain technology. Blockhain technology is currently being implemented in some systems. Some of them are banks that have started thinking how to implement the system blockchain on the system they have today. If calculated then I would much prefer bitcoin, I think that the future of bitcoin is good enough and I want to make the most of the opportunities I can get.

Bitcoin and Altcoins are both good in trading crypto currency. Bitcoin is the mother of all so it has a domino effect to all Altcoins. It is safely to say that both are good so it is ok to invest to Bitcoin and Altcoins. Putting all eggs in one basket is very risky so don't worry if you will invest to other digital currencies. When investing to Altcoins, just consider those top 10 so that you can never go wrong about them.

I think both are the profitable coin specially btc there is no doubt about that . for sustainable  crypto market we do need new altr in the market so many altr coin come into the market but not create a good demand because of the project was not good enough , i think after bitcoin eth is the best altr coin in the market .

bitcoin and altcoin are very supportive for common progress, and this can be a compact in progress. I really like both because it is very helpful to manage