> Seems like a waste to me, I'm not sure who would benefit.
I don't think there's a benefit from a lot of things people do around MAME. Doesn't mean many of them aren't viscerally cool and make your geek-senses tingle. Certainly a driver progress timeline in screenshots fits that description I think (but boy would I not want to have to make one).
People (or at least male people) respond better to visual stimulus. It's why software without screenshots available sells less. It's why I've been randomly adding tons of screenshots to the MESS wiki. (It also lets me play "MESS Slots", where I reload the main page until all 3 random screenshots are a driver I've worked on and/or a screenshot I took).