The problem they might run into with pegging a fiat currency to Bitcoin, is that Bitcoin works better than fiat already. Pegging fiat to gold works because fiat works better than gold for commerce and transactions. But Bitcoin transaction>>>>>>>bank wire, lightning/e-cash>debit card, and so on.
So all they'd accomplish by pegging to Bitcoin, is to instantly reprice everything into Bitcoin for us. Then it would be completely seamless for the NPCs to say "oh so I can just use Bitcoin directly like I do cash and avoid the headaches with banks and taxes like cash, I think I'll do that."
And pegging to a hard currency "for real" (redeemable) kills the banking system's ability to create unlimited credit/debt. Without that ability the whole system collapses tomorrow. So I think things would have to be really desperate for the parasite class before they tried that.
But who knows, today we have bonds down, dollar up, and Bitcoin up. That's the kind of crazy action that might push things to "desperate" levels faster than I expected.