I am all about letting the free market work, but if this were to become a thing, I do not realistically see how it could be done for longer than 5 days, which would make it similar to minting. So if you wanna lock up your funds for a higher APY, why not by minting what the protocol wants minted?
I could see a more realistic feature with a longer locking period being a mint optimizer. I don’t see how it could offer any sort of fixed APY but it would most likely be higher than staking.