This is true. An altcoin can have a good use case so it is in demand but when the market falls, they are still going to be affected. There are alts too that are in demand not because they are useful, for example meme coins.

The reason why is because they are hyped too much. A coin with no use case can die even if the market is still in a bullish mode. If some of them got lucky to survive, they will still be wiped out by the time the market goes into bearish mode. A lot of people complain when the bear comes but they shouldn't because bears have their own purpose. Not only that the market will be cleaner but they can also use the opportunity to buy more coins.