I will answer "YES" to your questions.
IMHO, a "Play-all" BJ player is a TRUE BJ Player!
With proper spread, "Play-All" should certainly achieve a 1% advantage, presuming not tipping.
Wonging looks good on paper...when done properly, creates the situation of m/l never betting in a "negative" deck...since I use BJ as my hobby/escape, standing around for 2-3 hours, in order to make a few bets, is not attractive!
And yes, even with a statistical advantge, you may go broke...but if same happens, you will have did so properly!
And, certainly, us "Play-alls" do not have any friction, and therefore, DO NOT GENERATE HEAT!
I hope this has been Helpful!
phantom007.