Though, it actually can run the full proper client, but the framerate is such a pain that it's hardly worth the trouble.

No idea why anyone would really want sl as a chat client. So you can chat with others that are doing things in SL you can't do?

Tech support for people who buy my scripts when I can't be bothered to crawl to my real computer.

Naturally, 'sl as a chat client' would be absolutely silly. But most tech support is conducted over IM.

And a lot of it involves manually sending people things that SL ate when your server tried to llGiveInventory.

..and what's worse, people insist on sending me notecards when I'm offline. You can't read those unless you log in.

Radegast is my favourite viewer