MB B3/F3 Dash Cancel is not that good because you don't have armor post B3/F3 cancel, so it can only absorb one hit during the B3/F3 preparition, characters who have more than 1 hit and can hit multiple times will blow up this tactic, unless you just B3/F3 without cancel it against some characters.
There is also, B3/F3 later MB Dash Cancel Option select. Option select because you can choose to dash cancel or to not dash cancel. the moment you press R2 you will get your armor, also good to bait and blow up 1 hit moves, like Killer Frost's Slide i.e.