Can really see why you'd use this, except for being able to see when somebody has read your message - which personally I hate because then people will be on my back wondering why I didn't reply right away. That's a reason I wouldn't use it.

I use a multi-protocol IM client on my phone, which has a constant link in the background to my GTalk, Windows Live Messenger, AIM, Skype, etc. - That way people can IM me any time from whatever platform they're currently on, whether it be computer, phone, browser, etc. But with Kik they have to be on a phone as well? That's really a step backwards, if they're sitting at their computer, logged into 5 separate IM clients already, and then have to pick up their phone to IM me. But it has obvious solutions.