It is only useful for tourney prep, that’s about the only situation where bos get serious effort put into them.
Still is a nice thing to have for tournament players, though.
Also doesn’t really matter if it gets revealed the first time you play the map, people won’t have the time to incorporate the bo into their gameplay in the middle of a tourney. The main problem is that you could spend 8 hours working on a bo for a tourney map and then some dude logs on, sees your work, spends an hour copying it and maybe refines it even more himself. Just destroys the desire to do any bo work unless you know the mechanics on how to break your replays (which is another barrier to entry for new high tier players).