There isn't much of a crit damage option for archers. If the crit was over 20, I'd say make one, because archers have high dex. In this case though, go for assault and get crit from an accessory.
I'd say crit if you use something like aim-type bale gauntlet.
While the crit rate itself isn't that high, combining it with dex boost acc would increase the change significantly.
This bow isn't good as a "main" bow, but for specialized use bc most enemies don't have defense, and the def penetration means it'll do 15% damage less than other bows at +5
if you aren't upgrading it, just as a stopgap until you get better equipment later, it doesn't really matter, but I would say in specialized use the higher ap gain from crit attacks let you use bell on someone else...