It's not an easy thing to invest our money in a long project because to wait for it we have to be patient,
If it is a long term altcoin project, it will defenitely fail. Being able to get into those which become groundbreaking is like the chance of getting a jackpot on a casino, because most projects are scams or failures anyway.
Bitcoin would not be that, so for long term bitcoin should be preferred. Altcoins are only going to be big in short term and before anyone can sell and cash out, someone would have dumped.
but in my opinion it is much better than choosing to speculate into shitcoins which risk may be greater,
Long term or short term in my opinion matter only for bitcoin, not altcoins if you want to trade in a sane manner. You may get more regular returns from day trading a new altcoin that hits the market, but you have to decide how to want to play it. End of the day, trading is not everything in life.