Ammo for archers?

[Shortpower]

What exactly does the ammo levelup skill do? They don't seem to have limited ammo so I don't really get it.

[Ozzey_Lee]

Increases their ammo capacity and the amount of ammo they gain per second.

[Freshairkaboom]

You only see it in survival. Archers will eventually run out of arrows. It's to counter funnel turtling.