I dont think its good use of the funds. The 11B treasury you are pointing to is largely a myth. A paper put out by Monet.supply and UCC.Hasu show just how much “11B is worth”. Its not even 1B…more like 150-200M USD which would get distressed even more if a liquidity campaign would ensue.
Liquidity mining is a great way to bootstrap liquidity onto a freshly launched project, but it proves to be quite parasitic in the long run. I´d say there is a better path to take than liquidity mining such as OlympusDAO has implemented. The problem with liquidity mining is that it leaves a negative footprint once it ends. Liquidity is loyal only to the person who pays. Why should UNI token holders bear this burden? What do they get in return besides the fact that they will get utterly dilluted?
The real problem for L2s is like you outlined in your point - fiat-on ramps. As long as the big CEXs do not adopt L2s, nothing is truly going to change. Liquidity mining will just burn through the UNI holders´ value.
Also, I think this is a duplicate thread. This was discussed in the past already…but I think it was for a migration from V2 to V3.