I can't believe you're arguing in good faith. Obviously just replacing the battery is better than replacing the whole device and all it's components just because the battery is bad.

The User above also said he bought two or three batteries, so he can swap them out when the battery is empty (I've also done this with my laptop) and distributing the charging cycles between the batteries, so they will all last longer.

If he wasn't a power user, he wouldn't drop money on two or three batteries in the beginning, and just buy a new one when the old goes bad.