[wkat4242]

Because it's an app used to share contact details. If more than half the people can't use it (and the people that can will not have a 100% uptake) there isn't much point in using it. It'll be a novelty for that one time you find someone you can actually use it with.

And Snapchat is one of many messaging apps. Personally I've never used it and I have 6 different chat apps on my phone :) This thing is a really new idea and it only really works if it becomes a standard. People are not going to carry 6 different contact card sharing apps because it'll be a mess.