Yes, I'm afraid I'd forgotten the question I asked over two years ago which was never answered.
No worries... it was an excellent question! I came across it in my search to try to get a handle on the
history of the whole thing. The applet is a great idea (and I'm sure the developers agree, otherwise they
wouldn't have taken the time to create it) - and it's purpose is detailed in the docs.
I got the impression the feeling was that since it worked fine under KDE there was no need to
have a KDE specific version. Of course now, ahem, it isn't working. :-(
There are a whole slew of applications which managed to get it working, including Chrome/Chromium - so I do have faith that eventually, they'll get around to it.