I don't see why the answer has to be so complicated. All this is, is a long run win of whatever the match play value/free bet as long as its used properly in a game with +EV. Even if you were playing a game with a 1% house edge you would only be losing 1% of overall bet in the long run.
Same for free slot play. You would play video poker because it has the best return in hopes you will get that slot play in cash.