What is MSN good for? Well, isn't it the most popular chat program at the moment?
Well, in other platforms it may be the most popular chat program because it supports some sort of video streaming. You can see the person you are talking to. (I hope i'm not spreading cr*p right know, since i don't have any experience in other platforms)
On AmigaOS/MOS? I don't think so. At least not for me and for many other Amiga users. The IRC is the most popular protocol, afaik.
Anyhow, to answer your initial question: I would be interested in it if it would support that missing feature. Otherwise not.
If i want to communicate with someone, i will use the e-mail. If i want to do it in real-time, i will just use the IRC. Because there are good Amiga IRC clients and because i'm used to it.