They, the regulators, do not care. The Bitcoin ETF does not create inflation because it is just another financial instrument and all financial instruments based in Fiat, denominated in Fiat are FIAT condiuts. Regardless whether it is concrete, buildings or stuff. No more Fiat will be created than is getting created anyway which is always going to accelerate because the Fiat denominated debts are more than the actual Fiat money supply. As a debt instrument the Fiat currency created out of debt will never be enough to fulfill the Fiat denominated debt because the debt was not based on any capitol in the first place.
The reality sinister thing about this is this:
If I sell my Bitcoin for Fiat someone has to create Fiat to fulfill that buy. If so the currency is tied up in other debt instruments the new currency has to be borrowed!
Jack has a balance of 47 thousand dollars. Jim has 1 Bitcoin. Jim sells it for 47 thousand USD. Jack agrees and goes to his bank to get the cash. Jack's bank doesn't have it so he gets a cashier's check. Jim gets the check. Jim deposits the check. No money has gone anywhere. The settled debt has just transferred from bank A to bank B. But really both banks have just accepted two new debts since there is no collateral, no fractional reserve and no regulators to check that it's met because those rules changed in 2020.
It's an I owe you if you get in trouble because the FDIC will step in and or another bank will gobble up our debt or we'll go to the last lenders window, the Fed. Meanwhile the FDIC doesn't have any reserve either, so there is that too.
It's exhausting but it's true. Because Jack deposited over time his accumulated Fiat his back has a record and must honor it. That's it.
Next time you go to the bank ask to see the reserve of cash on hand. My credit union has to have this in the wall. If you want cash of a larger amount you have to ask them ahead of time to get that sum together.
The BITCOIN ETF will not add anything new. Nothing at all. It will be held in the same "trust me" system that already exists. Someone will own some Bitcoin but like all the assets in the banks, it won't be you. Don't be surprised if they even burn Bitcoin (which is impossible but that's another story).