In my experience it takes much longer than 5m but I also have an old mouse. It forces me to stop using the mouse while charging it. I own a second cheap mouse for this reason alone, to use while it’s charging. With their keyboard I can charge it while continuing to use it, so if they really didn’t want to allow for use while charging, it would seem they’d do the same with the keyboard.

A few reasons:

- it takes longer than 5m IRL IMHO

- the message to charge it always pops up at the most inconvenient times

- and 99% of the time, it pops up either when there are still like enough % charge for hours (which encourages you to ignore it if you're busy atm), and then again when it's too late and it's shutting down pronto