Multi-hit aerial shield pressure?

[JeezImSoBored]

So i've been wondering, why doesn't anyone use multi-hit aerials for shield pressure?

why do falcos not use fair but nair instead for shield pressure?
same for fox, why do they nair and not dair?

shouldn't more hits stun them for longer ?

 

[Cactuar]

Landing lag.
Crouch Cancelling.
SDI.
Hitstun anticipation and on the fly adjustment required to l-cancel.