few and far between if she is using it else she’d merely LoS them.
and those are limitations. not restrictions.
rez is a restricted skill (requires a dead ally), GA is a restrictive ability (requires ally), zarya’s 2nd bubble is restrictive as requries another ally.
moira has literally nothing restrictive.
she can use her entire kit at any time.
(excluding ofc if she is hacked.)
its been that way since day1 of ana.
rez has a big caveat…a ded ally.
a cast time where she can be killed.
and a 30sec cd.
Bionade has insta cast (and travel time)
can be used to heal ally or dmg/block healing of enemies. (only thign that blocks it is barriers which are easy to get around/break)
and a freakign 10sec cd.
blocking all of healing is effectively removing 2 of that persons team to a bionaded person. excluding zarya bubble and mei iceblock NOTHING can be done to counter it.
and it isnt only my view. its actually been a forum topic for awhile (just has a long between topics about it)
then why is ana is #1 healer across all tiers…except bronze where mercy and moira beats her (bronze ppl lack aim/awareness for snipers) and silver where moira beats her.
and funny thing is…rein is #1 picked hero at same time 
so don’t “nothing if enemy team has barriers”.
and again. this is PC. (as again idk how console is)
many places are actually doing htis.
some are even doing online classes.
Doubt my town will as their public school rarely ever cancel stuff.
and 1 before it was started in july of 2018