Bitcoin halving is coming so Bitcoin is gaining more popularity than altcoins, after the halving of Bitcoin reward and during the period everyone is assuming that the bull market will start people will start shifting attention to altcoins and that's so they can profit from altcoin.
whether it happens to everyone or not, for those who are quite fanatical about Bitcoin, all they do is buy or trade Bitcoin in any market trend conditions.
Maybe in the past, some traders paid attention to the method you explained to get better profits. but now I just believe Bitcoin confidence is increasing and altcoins may be some to watch with a possible pump following the upcoming bull trend.
I personally just prepare my Bitcoins, and trade to increase the quantity of Bitcoins I have.