Does reversibility actually matter anywhere outside of consumer merchant payments?
If you send a wire transfer, it can't be reversed. If you write a check, you can't reverse it once it's been cashed or deposited. You can ask for a stop payment before a check has cleared, but you can also be accused of check fraud if you ask for a stop payment under the wrong circumstances. Outside of the payments domain: if you buy stock on the stock market, you can't reverse a filled order. You can sell your stock, but you need to sell to a new buyer at a new market price.
Even in the modern fintech space, not all transactions are reversible. A Zelle transaction can't be reversed, for instance:
https://money.stackexchange.com/questions/86920/can-a-zelle-...
All this is to say that true reversibility is only available in certain cases. It is something that financial institutions offer when they know that the funds recipient is a merchant in a captive relationship with a financial institution, where the merchant will most likely be able to fund the reversal by offsetting future unsettled payments that are yet to be reimbursed to the merchant. It works only because merchants are dependent on financial institutions, and do not have the negotiating power to demand instantaneous, final settlement.
I very much doubt that financial institutions will want to (or will even be able to) extend reversibility to other transaction types just so as to deploy it as a strategy to prevent open blockchains from becoming predominant.