No I don't trust leaving any $$'s in MPL at all.
The only reason I use them is for small wins, being in the US most places you have to win $350 plus in order to withdrawal at all if you don't have a wallet. So I opened an account with MPL simply to be able to cash out smaller amounts won off free chips with 5 or 10x max cashouts.
It gives me a little here and there to be able to us to play at some RTG's - if I were to happen to win an amount of $500 plus I would definetly request the withdrawal via Check or ACH/Bank Wire ONLY if Check withdrawal was not available.
It is nice to have "a" wallet again for however long it last (which we all know too well they could close down tomorrow) but it is a way to receive a payout faster if I did happen to hit something small, than I have a little to use to play with without having to use the $$'s I set aside for entertainment and I don't have to deposit using a CC.
The most I have had at one time in MPL is $300 and I the longest I have help any funds in MPL was about 48-72 hours.
This way has worked for me so far - but I don't think I will ever trust any wallet again enough to actually request to have a large payout paid to the wallet, If lucky enough to win a decent amount I will request they send via Check.
Just my 2 cents ...