I think converting one of those would be a great idea... I've seen pics of a couple of them that had been converted to MAME machines & they are basically the same as any other mini cabinet...
I thought of doing it a few times, but the ones that pop up around here always end up selling for too much.

(Super Auctions in Mesquite, TX)...
They would make great 1 player games. As far as 2 player.... eh... I wouldn't do it... That would be a little cramped.
But if it's free... Make a 1 player for starters & maybe you could sell it to fund starting a full-size 2 player MAME machine.
That's what I would do anyways...
