[dmoy]

I mean from an EE perspective it makes some sense, because you save some on circuitry (not like a lot in absolute cost, but your cordless beard trimmer probably doesn't have a lot of margin).

So the real reason is probably just to make it cheaper. (Well maybe not in the Mac case)

[lloeki]

Cordless trimmers are generally waterproof because some people use those under the shower.

Having them non operational when charging can very well be a safety measure so that they don't use it while plugged in.

There's really no excuse for headsets like Bose where such circuitry is a rounding error in the hefty price tag.

Hell, they even have USB circuitry that enumerates as an actual device on the bus but couldn't be arsed to have it be a proper audio class device.

[wkat4242]

Yeah in case of the beard trimmer it's because it uses quite a lot of power so you need a beefy adapter to run it. These often still use NiMH cells and trickle charge with 100mA or so.

For a mouse this is all irrelevant because it uses so little power that it can easily be powered by a regular USB.

Also, many bathrooms don't have sockets anyway. At least not nearby (and cooper is expensive too these days)