maltz

Rechargeable lithium cells are NOT the same chemistry as lithium coin cells, and are significantly higher voltage.  When fully charged, the voltage difference is 4.2V vs 3V - an increase of 40%.  That'd be like plugging a computer expecting 115V into an outlet supplying 160V!  Some electronics might be okay with that, some might work for a while but under increased stress, and others may just die immediately.

For the effort of changing a coin cell (which you still have to do when the cell is rechargeable) it's not worth the risk for me.  YMMV.

No mention of the notification sounds?

I've never really understood the popularity of wireless mice and keyboards, but especially keyboards.  Mice, ok, the cord can be annoying if it tends to get hung up on something, but rearranging the cord or desk layout has always fixed that for me.  But keyboards are stationary.  What's the point of it being wireless?  And having to mess with charging and/or changing batteries is a hassle.

That's not to say there aren't ANY use cases - I have a wireless keyboard/trackpad combo for my HTPC for when the IR remote doesn't suffice, for example.  And our conference room at work has wireless so the computer driving the large display there can be used by anyone at the table.  But the typical "sitting at your desk using your computer" case I don't really get.