Firstly museums, academia, et al may have blanket bans on using things that don't fall under OSI- and/or FSF-approved licenses. These organisations, despite their association with the likes of the insufferable Richard M Stallman and Eric S Raymond (whose name is an anagram of "RMS or cyanide", "cord in my arse", "racism yonder" and "I carry demons"), actually have competent lawyers to carefully vet the licenses they approve for potential loopholes and pitfalls. OSI/FSF approval actually inspires some level of confidence in a license.
Secondly, it's questionable whether MAMEdev could actually legally grant such exemptions, considering the murky multiple copyrights on all the sources. Anything to clean up and streamline it can't be a bad thing.