So I've got an A9 keyring that I got a few years ago for my BS Century.  All it did was turn on the radio and turn it off again (I don't have a TV or lights).  So when I got my BS4 I had hoped that maybe it would do something else useful, like change sources if you pushed the Audio button a couple of times.  I dug it out yesterday and tried it out.

No. It's not useless. It's a keyring... ;-) ;-) ;-)

Ok ok. And you can switch of your complete B&O stuff when leaving your home.

Except for the keyring- and the switch-off-function it could be called "useless"...

I think the most use of it, is in connection with Light control.

I primerely use it for turning on the lights when I get home after dark, or to switch everything (Sound + light) off, when I leave the house. I may not be of much use to those who does not have light controllers. However the all off cannot be replicated by the Beo4.

Maybe the Beo5 can be programmet to include an all off button.

I agree with you! The A9 is not the most useful device made by B&O!! It is quite tactile though and is a nice keyring. I have not used mine as a remote for years - not even sure the betteries work - but is a nice keyring!!