my guess is that shotblocking will be more effective against guards driving to the hoop, and marginally more effective against bigs trying reverse layups.
my guess is the intended effect is to make guard skill builds emphasizing IS, driving and OD less effective and have an implied effect that guard skill build becomes more about offering an outside shooting threat.
This is enormously difficult to get right, and all credit to them if that is what they are trying to do, and they get it right.