Same kind of reasoning could have been applied to bitcoin at the start. Not that I have an opinion about this or that altcoin, just pointing out the hole in your rationale.
What hole tho? The impetus for creating Bitcoin against the other existing forms of payment/banking systems was clear.
How about the delusional hole in rationale that says once we have a single crypto payment system that is secure, decentralized, functional, and popular (w/ users, brokers, exchanges, and merchants), that we need another one? Or a thousand more? Ten thousand more?