Actually, it should be easier to convince these people. If they are already used to 2+ IM apps, then what's the issue with adding one more? Ask them if you are important enough for one more app. ๐
Problem is for people who only have one app, and find it too bothersome (or confusing, for non-techie / old people) to use more than one app.
That looks really cool. Would love to see if there is something like that for android