I think "low end bulk buy batteries" is the key here, not "cheap equipment". A battery can't tell what kind of device it's in. And the difference between, say, a steel contact and a gold plated one has to do with the resistance (electrical, not mechanical) that the battery must push against. High resistance contacts will deliver slightly less voltage to the device being powered. And will eat up a small amount of battery capacity and waste that as heat (but it's an infinitesimally small amount). That may affect efficiency of battery utilization, but the battery really doesn't care about that and won't leak just to spite you for not having gold plated contacts. Pairing dissimilar metals together can (but not always) have negative consequences (corrosion, etc.) but it's not like good equipment is made out of the same metals that batteries are (similar) and cheap equipment is made out of different metals (dissimilar).