I don't understand this kind of comment. Why not just use both? You don't need to convert your whole networth into crypto, only in the currency you actually need: to use the (decentralized) service you need to buy the service's cryptocurrency. The end user is still paying for the service they use, but instead of being a "balance" on a private centralized database it's an actual balance on a public ledger. The only problem is that right now you need a wallet and to actually buy the token, but fiat on-ramps and wallets are getting better by the day, and the UX gap is closing. Eventually people will use "cryptocurrency" without even realizing it.