Sure, it requires special tools, but isn't a battery change on a quartz watch pretty easy? I think the going price for a battery change is like 10€. There can't be that much hard work involved with pricing like that.
I would respond that replacing a battery on a modern iPhone is similarly easy. The tools are plastic, cheap, and as others have noted, are often bundled with the battery. The only price delta here is the cost of the battery itself.
Sure, it requires special tools, but isn't a battery change on a quartz watch pretty easy? I think the going price for a battery change is like 10€. There can't be that much hard work involved with pricing like that.