Just my limited experience based opinion here.
I have now zeroed in and shot three different crossbows out to 50 yards. All using both their factory supplied arrows with a straightness factor of 0.003 and with, Black Eagle Executioners, BE Zombie Slayers with a SF of 0.001 and in the case of my Excalibur Assassin EXtreme custom made indexed matched arrows.
My Assassin EX 400 shoots a 450grn TW arrow at 366fps
My Wrath 430X shoots a 450grn arrow at over 396fps
My 10YO Wicked Ridge Invader shoots a 400 grain arrow at IIRC 310fps.
As has been said at distances UNDER 50 yards shooting a FBBH with a CD of 1-3/8" VS FPs at or under 400fps I saw no significant difference in accuracy between arrow types. I would not hesitate to hunt with any of the factory arrows that came with my crossbows.
Having said that the higher quality arrows I own have in my experience so far one major advantage VS factory arrows. That being consistently more accurate with far fewer if any fliers that stray outside of my 2" bulls eye with a FBBH.
As I prefer to shoot FBBH's using a higher quality than factory arrows is in MY OPINION a must as I have seen my BE ZS's just flat out shoot better than my factory arrows with larger OD FBBHs and do so consistently.
Is it a significant enough of a difference to REALLY matter? In all honesty no. But I am a reloader and rifle shooter who is hopelessly addicted to achieving maximum accuracy so if higher quality higher $$$ arrows reduces my over all 50 yard group size by 15-20% I'm going with the more costly arrows.
IN MY opinion if you're shooting below 400fps, 50 yards and under and using mechanical broadheads you should be just fine with factory arrows that you have test fired and confirmed fly well.
If consistently hitting a 1" dot at 50 yards is a must for you then higher quality high $$$ arrows are a must have.
My custom made indexed matched arrows for my Excalibur Assassin EXT are literally same hole arrows out to 50 yards.