That sounds good, as long as a transition to native all at once can happen smoothly without resetting the network.
If ERC20 is then still available for bridging, even if it’s not used for payments any more, it can be useful for storage / smart contracts / DEXs etc.
After native is added as an option, then we need our own internal exchange. Once we have that, then we don’t need CEX or other DEX. Just install 
go to the exchange and convert fiat or other crypto into native token. No listing or dependency on other apps or companies - real autonomi, real defi, real decentralization.