The loom points add no value to the arrows because you rarely run out of arrows as it is. Not to mention having an extra 3 arrows on a stack of mw bodkins isnt going to do shit for you.
That depends on your build.
If you go 1slot bow, 1 slot weapon and with 2 stack of arrows you will not need more arrows probably. Same with 2 slot bow, 0 slot weapon and 2 stack of arrows.
but if you go 2 slot bow, 1 slot weapon and with 1 stack of arrows and have some melee skills it isn't bad to have about 5-8 arrows more.