I don't know what kind of aspect when said useless altcoin. Some of altcoin many kind of aspect like, economic, influencer, finance, tech and anything. all of them usefull when altcoin to apply one. when bitcoin reach 100k, no problem with altcoin, it will be followed.
even some altcoins have better growth than bitcoin. if the small capital investment is possible the altcoin is the best choice, because to be able to invest in bitcoin need more capital. bitcoin and altcoin have their own markets and they also have their own growth, we cannot judge so simply.