This is going to draw a lot of comparisons to the Ornate Bow for obvious reasons. They're two-handed weapons that use alternate stats to attack and have functionally unlimited ammo. The Ornate version is a very specific tool for a very specific style of play; you're spending a serious investment in cash and XP on a weapon that uses two actions to deal heavy damage with one accurate attack.
The Enchanted version is... not that. It's cheaper both in cash and XP, but also all around less useful. You get less bonus to hit, it deals less damage, it takes up more slots, and while you don't have to reload it, it exhausts to attack. And that last part is the real killer.
3 damage is the magic number. Many, many enemies have 3hp or less; 87 enemies have 3hp, compared to only 62 with 2hp. That means for the extra 30% enemies that you'll encounter, one shot will not kill it. And if you're packing a weapon that focuses on or , you almost certainly don't have the to just punch it for that last point of damage. You'll then be relying on a spell to actually kill it (as a mystic), or evading it (as a survivor). And you're filling up 3(!) valuable slots for a weapon that can't seal the deal, leaving survivors with no hands for any other weapons and requiring mystics to dedicate both of their arcane slots to combat spells.
Not only that, it loses out to the Ornate bow on DPS too. If you're fighting a boss and not engaged with it, the Ornate bow can fire, reload, and fire again, for 6 damage in a round; the same as any standard 2 damage weapon. It's awkward, but it works in a pinch. The Enchanted bow does 2 damage per round, full stop. The Ornate bow can benefit from Venturer and other reload abilities, the Enchanted cannot. Multiclass Guardians can't even use Vicious Blow to push it over the 3 damage sweet spot, because you cannot commit skill cards to tests without matching icons.
Okay, so you want to use it anyway, because it's cool. Who can make use of it?
Candidate #1, "Ashcan" Pete. Pete can discard cards to ready other cards, meaning he's the only character that can actually fire the bow twice in a round. 4 damage is sufficient to kill most things, and It also leaves Duke available to investigate, or squeeze in another 2 damage at a slightly lower bonus. A solid option.
Candidate #2, Rita Young. She's a very strong user for the Ornate bow, but if you aren't filling the primary monster hunter role, you might find $4 and 3xp too pricy for a weapon you won't use all that often. Her ability lets you use to squeak in that final point of damage, so you aren't up a creek against 3hp enemies. She can also evade first, use her free move to move to a connecting location, and spend a charge to fire backwards, ignoring Retaliate. Theoretically useful.
Candidate #3, any dedicated monster-hunting mystic that normally runs with Wither. Wither already requires you to double-fist combat spells by virtue of only doing one damage, and the bow slots in nicely at the 2xp median if you don't want to drop 4xp on the upgraded version. It can do an admirable job at stretching Shrivelling charges and is cost-comparable to other options, if you don't care about your hand slots.
Candidate #4, anyone crazy enough to build a character around hunting Aloof enemies. 3 uses of Marksmanship in a single asset that doubles as a weapon is actually pretty economical. Dunwich, Circle Undone and Innsmouth all benefit from being able to snipe aloof enemies, if you don't mind handicapping yourself for the remaining 80% of the campaign.