Messenger 7 Mac Released - tell me why

As a long time user of Adium for the Mac, plus of course Apple's very own iChat, I left Microsoft Messenger behind a long time ago. When a new version came out, in the past, I tried it, but could never really work out where it would fit in my portfolio of applications. So I may well skip the newly released version 7.
Sure, I understand that users come from a PC background, where all their friends use Windows, but then is that not where Adium comes in. In some situations, I tell friends if they really want to communicate with me in a video conferencing scenario, to "buy a Mac". This might seem a bit extreme, but I have converted a few like that.
For those of you who use Messenger, please share in the comments, why do you use this app? and what are the invaluable benefits?