As descentralized alternative, none.

The Brazilian experience with digital cash, not full CDBC yet, made almost every Brazilian to adhere the use of PIX, a digital FIAT but not a CDBC.

It's pretty much like Bitcoin Lightning. As a matter of fact, Central Bank copied the Lightning user logic. The difference is that the "wallet" still being a bank.

My point is, if it's practical, users will go after it.