In message , at 08:49:30 on Wed, 17 Jul
2019, Anna Noyd-Dryver remarked:

Now you mention it, I did once have a case for a smartphone that had
power bank integrated, which meant having a pass-through connector. But
the battery inside that died very quickly (a matter of months). The fact
they are so rare makes me think there's something systemically wrong
with them.

Is it also perhaps because the backs of phones increasingly have buttons
and camera lenses/flashes and so on - which would tend to get obscured
unless the case had exactly the correct cut-outs in it.

The case has to be designed to fit the size, shape and connectors of the
phone anyway; putting holes in the right place for camera, microphone,
speaker etc isn’t rocket science. Plain cases for every variety of phone
manage it, so do the powered cases.

I just went to Amazon to look, for my LG phone. A choice of 13 products,
every single one "Currently unavailable".
--
Roland Perry