I do have server expenses that map directly to processing work done for individual customers, so there is a quantifiable amount of real money lost at times. But at the end of the day, I still don't want somebody's fourteen dollars enough to fight them for it (even if it means I also lose another $5 in real expense and a few more in chargeback fees).
But you're absolutely right. If it were physical goods or services, I'd fight those chargebacks for sure. (Though it'd be a lot harder for one of my deadbeat customers to plausibly claim that he'd "forgot that I mowed his lawn").
