buying shares is not buying bitcoin. its investing in corporations shares where the corp assesses collateral of a trust the corporation holds (as a secondary entity's valuation)
meaning the shares have no actual ownership rights nor voting rights over the btc, as the btc is held in a secondary entity(trust)
not the share holders claim of the main corp
I remember this disscusion on gold and silver ETFs a few times, and it was "can you take out or have delivered the gold and silver from the vault". I guess hear it would be can I have the keys for my shares in btc