If someone doesn't understand why crypto is good and has no fundemental investing reasons for holding crypto then what you're saying is right... either that person is a trader, or they are just someone throwing money at something you don't understand.
Market cap of world currencies? Trillions. Currencies and bank reserves exchange in the trillions. That's what I mean. And you should never have 100% holdings in 1 coin. I could ride one of my coins to zero, but I'll still have plenty in others.