I'd be convinced that saving on the wear and tear of swapping boards would be the best reason. Let the switch be the switch instead of wearing your boards down.
Mind you I've done zero jamma research but when I see images of them for sale here and there I think about wearing my old NES carts down to nothing. It could be different IDK yet. I'm inspired to look into jamma more.
I'd really just like to have, when all is said and done, a MAME cab with honest to god Soul Calibur 2 and Area 51 Site 4, maybe gauntlet legends shoved in there and if I'm lucky on a switch to choose before turning the cabinet on. Choosing which power supply gets turned on i guess. That said I'll look into jamma stuff finally see what I can do. I could handle running 3 sets of wires. I've thought about making a CP for each and put all the hardware i could inside of that then swapping CPs around. That's just no good, too slow to change things too much work, someone else wouldn't be able to do it. which might be a plus in itself, hmm.
Looked into jamma. looks like it would be good to have as backup or alternative or just anyway.