Necessity?  Nope.  

if you have a colt based lower, i.e. you're using colt (or uzi?) magazines then you're fine with any 9mm barrel from what I understand.

If you're using QC10's glock lower then the QC10 barrel feeds considerably better than the Adco barrel I had.    That's very specific to the Glock lower and glock magazines and it could be very specific to my glock lower and adco barrel.  

Bottom line if you're not using Glock based lower/mags then don't sweat it too much.  

Additionally if you're shooting nothing but FMJ RN you'll probably be fine but I don't like not being able to shoot HD style loads from every weapon and the Adco barrel + glock lower combination didn't like JHP's.   It deformed the mouths and in a couple of cases the impact was enough to cause, IMO, a dangerous level of set back, i.e. the bullet was pushed deeper into the case. This decreases the space for the powder to expand in which increases pressure. Pressure spikes are bad.   Kind of like a cherry bomb in a beer can will blow it open but drop it in in a 5 gallon sized aluminum and you got just a muffled boom.