Mostly, I agree. However, part of why it has a cost is to be a sink for gold. Sure, it’s not much, but it does add up. However, there are better ways to handle it than to track arrows.

Just make your players occasionally pay for upkeep of their gear when they’re in town. This could be themes as repairs for weapons an armor, more arrows, spellcasting supplies, food, etc. This does two things. You can give them more value in rewards and it makes them feel like they’re actually adventurers, not just game characters.

Alternatively, scale rewards down. They don’t have to know about it, but if they’re not paying for supplies then they’re going to get more value than is expected (by the rules).

Or, the final option, just ignore it. It theoretically adds up to a lot of value over the course of the game, especially for spellcasting, but who cares? If you notice they have enough money that they stop worrying about it then you can do something.