While "approved" boards are a great idea, it's not feasible in the current tournament environment to enforce that. Most tournaments run on a pretty tight budget. Trying to validate and approve boards for every possible marker, test those boards to ensure they haven't been tampered with and still allow players to set up the markers the way they want to just isn't practical right now. maybe when the sport gets regular TV coverage or major outside sponsorship it will be practical, but right now it's highly unlikely.
(if you want to make the "but boards are cheap" arguement, I recommend doing a search on previous threads. Manike has pretty well debunked that arguement in other threads)
What is possible and enforcable are BPS caps. While true semi-auto is a great idea, the inability to enforce it allows a huge gray area that players can (and will) take Advantage(PB) of.