Environmental concerns are the one for me.

People mention non-refundable transactions but... That's already how shit works. If you wire some fiat funds to a random account, they're gone. That can't be reversed. What we have is over the years banks/companies/insurers have developed anti-fraud measures, escrow schemes, etc, to make it as easy as possible to help people who have been scammed out (for the purpose of making their customers happy, obviously). L2 solutions will do the same thing. People who are concerned about being scammed will fall into the pool of customers who like all the anti-fraud protections at the cost of privacy and control.