Thank you for pointing that out. I think it's great that they build that in such a way that a deceased battery is not "end of life" for the product.

What I would really like to see is a self-contained taillight that used, say, a 16340 battery that could be swapped easily and quickly. So, something where one could carry a spare battery for extended run time.

I don't have high hopes of something like that becoming available, as I think it would appeal only to a relatively small audience. People who want greater capacity already have other options such as external battery packs and/or dynamo setups.