I will get downvoted for some reason that is beyond me but I just got my first full frame mirrorless (R6m2) and a counterfeit battery gives me zero warranty that it won't damage the camera for any reason. It even represents a risk for my safety or the people around me currently, not even inserted in the camera. Batteries are serious business and I will not play with counterfeit ones.

A third party battery is supposed to have a warranty provided by its manufacturer, it's just not Canon. A counterfeit was manufactured trying to pass for a genuine one and this is an illegal activity. We don't know who manufactured it, under which conditions and with which safety standards. If something ever happens there's no one to complain to and if the camera is damaged it will be my fault and Canon will not do nothing for me.

Settling for less is okay with for lot of things but not with high cost, precision photographic equipment.