1.) dash is the most controlled dismount
2.) as with literally any movement: body awareness. even if you're "pure parkour" or whatever, it's not an excuse not to learn spins/"unnecessary stuffs." every movement helps with control. if you want to be really effective, you can't think in moves.. you need to be able to do everything you're capable of, and you need to be able to pull it out of your "bag of tricks' when you need it. example.. i have a lofted bed, about 7 foot up. one morning, i woke up because i leaned too far off in my sleep. i was falling. a backwards spin was the only way to save my neck from taking a 7 foot drop. some would immediately be daunted by having a backflip forced upon them literally first thing in the morning, but hey, it can totally happen.. every movement can be useful, and it only takes one f#ck up to turn you into "ermahgerd mershed perterters".
remember, "we don't rise to the occasion, we descend to our level of training."
3.) if you can do a dash, you have a "full spectrum" on your feet first vaults. learning lazies at all angles and neglecting dash is like learning all the different ways to do a simple/safety, but neglecting kongs.
4.) it's the best vault to do with a height-based running jump. lazy or speed you have to jump sideways, and kongs you'd either have to punch hard as hell or do them split legged (which is quite awkward if you're looking for height,) and reverses you'd have to jump backwards (and f#ck that. lol.)
5.) but if you ever need an excuse for progression, remind yourself that you never do. one thing leads to another, and many things lead to control. control leads to self-awareness, and self-awareness leads to a balanced life. TRAIN.