You're just trying to get the device into a known good state.

The truth is that it's rarely worth trying to find the root cause of an issue unless it's a frequent problem.

Something somewhere went wrong. We don't know if it's a hardware or software issue, so we'll try a solution that covers both.

Powering the device off stops the flow of electricity, and waiting a few seconds makes sure that any capacitors (think of very tiny, very fast batteries) bleed off the power they've stored. Then turning it back on makes it go through the full startup process which is likely to result in a working state.

Not saying this is the answer to your question, but generally, it's the hardware/software unaccounted-for states that can't easily be recovered from. So, rebooting would hopefully get it in a known "clean" state, and hopefully, not falling into that unaccounted-for state again.

Shitty, but works with some other things too. Angry, frustrated, hopeless? Sleep it off, maybe (not guaranteed) it will be better tomorrow.

To be fair, this is a recurring experience on Linux, Mac, and Windows of varying generations of equipment. As an educated guess it seems to be hardware states that cant be reset from software for whatever reason.

Could also be that the Bluetooth kernel module is a loadable one, and if you've updated the kernel (which will usually take place pretty soon after a first install) then you won't have the matching folder of modules to load up until you restart. Arch is a bugger for this - I've an external mouse that works fine if you keep it plugged in during a kernel update, but it won't be recognised after an update until you restart again. Not a big deal - you can choose when to update.

So… this is Linux… You could try restarting the specific service. If that works. The advice was dumb and it was a software problem.

If it doesn’t, it was some type of weird hardware problem.

In my experience, though simply toggling the antenna (using the gui widget next to the clock, or gui settings-> Bluetooth off) works

Can't confirm, but I would assume that there is a capacitor in a few bluetooth modules that keeps some of the components charged, and that they only try to comminicate with the kernel after a power cycle.