I fully agree, this proposal does not make any sense. We are trying to "fix" a "problem" by throwing money at it.Spending anything on liquidity providers doesn't make any sense for me:
1) you can't really prove were they working or not
2) they will be mixing with each other because they can't distinguish themselves from "normal" users (otherwise there is no anonymity left) bloating blockchain for no good
3) $50 is way too much
That's not a fix imo. If you want to support mixing - open your wallet and mix. I'm doing that for more than a month now with darksendmultisession=1 (which means it's even more aggressive than the liquidityprovider=1) and darksendrounds=16, restarting when it's done. And it cost me ~2.5 DASH/month which is nowhere near ~20 DASH proposed.
I say no.