I don't know how this specific thing works, but I don't really see any fundamental problem with mixing and matching. If you believe in the benefits of crypto, then 50% crypto is still possibly better than 0%.
It's not like I forgo a lock on my front door just because my windows are made of glass.
The primary selling points of cryptocurrencies are all hinged on the promise that they are decentralized and can't be controlled by a single entity. Without that, all they are is a new version of PayPal or a credit card network that requires many orders of magnitude more compute resources to maintain.
Currency isn't a homebrew computer or backyard car project; it is either centralised or not; there is no in between.
Blockchain with central authority is the worst of both worlds.