The technology can just as easily be applied for other purposes, mandated by an authoritarian government to be the only legal way to conduct commerce. You'd use it not because you want to, but because you want to avoid their ire.
There's literally no reason to use it at that point, just make a simple db of account numbers and balances.
It would be actually possible to use a government's money in various new ways. Think of what could happen in the economy if the government provided flexible and free payment services.
(Which is exactly why they'll never do it, but just pointing out that a government-controlled blockchain for normal people would have a LOT of applications)
Actually my government already has rules on that. Using my debetcard at a store, withdrawing money from an ATM or transferring money between bankaccounts is free.
Its almost as if we live in 21st century already!
Second, go to your nearest store, bakery or whatever, and ask them just how free debit cards are.