The way I understand it, there is no technical issue.
I don't think it will be a particularly great breakthrough though, and it would cause plenty of chaos in the short term.
The second paragraph has a brief description of roles of the ETF distributor and approved participants in ETF share creation.
My thinking is that (A) Bitcoin is extremely volatile, partiallybecause it has a large number of inexperienced/uninformed people trading it, (B) volatility makes it riskier for the authorized participants to convert BTC to and from new ETF shares. So they need a larger discrepancy between BTC and the ETF to pay for the risk (C) bigger discrepancy reduces liquidity and also stirs up the crazies, both of which feed back into (A).