My frustrating experience with lots of older tech like cameras and laptops is that the battery formats are constantly changing, and none are being manufactured in the required format 5+ years later, when I'd really want a fresh battery.
So even though it is designed for easy field replacement, it is effectively obsolete because the only product available is some dodgy counterfeit part. You never know if it even meets the specs, avoids being a fire hazard, and isn't an outright fraud like relabeled old batteries...