For reliable instrument function
At first glance, chargers and batteries do not seem to be especially important accessories. Perhaps they do not seem worth paying attention to for quality or origin. Experience shows the opposite.
Instruments and their electronics react sensitively and need a reliable power supply in all environmental conditions. Batteries and chargers are also exposed to these conditions - some will function, others might and some not for long or not at all, under certain conditions. That is why the quality and efficiency of the originals also counts for batteries and chargers.