Even the BNB, what if Binance got hacked or something happened and it fold up? BNB will crash and become useless. I used it as the example because it is the one you recognized most and the first among them if marketcap is used. Any exchange can get hacked and this may cause their token to become useless. Go for decentralized coin like bitcoin.
I think that BNB, is worth holding because it's backed by Binance, being the top exchange among other exchanges, but speculators categorize exchange tokens that if anything happens to their parent exchanges like being hacked, that the investors capitals in the tokens will go down with the exchange. However I still consider any top altcoins to be worth holding like Ethereum and BNB, you know that they've built solid reputations in the crypto market, so if their prices dips, it's only a matter of time and they'll begin to pump again. Let's not forget the king of them all, being Bitcoin, a decentralized cryptocurrency that guarantees ROI.
i think we overlook the fact that BNB in itself have Binance Smart Chain backing it up like even if binance somehow performs bad or the exchange got hacked, i think its different entity altogether, the fact that there are many dapps could probably hold up the value quite well when something bad like that occurring.
basically binance has created really good way to secure their BNB or at least give some safety measure for it when binance facing problem so that BNB will not get affected.
so therefore im not really worried if about the value of BNB in the future, even with many problems, its not gonna get shaken that easily.
instead i would worry about other exchange coin that only have utility of cutting those exchange fees.