Well, who doesnt and we still use different ways to communicate with people (Skype, Facebook, IM, Forums, SMS, WhatsApp, etc...) so your comment is as redundant as the amount of ways people use to communciate with each other.
Even tho the basic idea is to allow the end user to chat with someone through her/his smartphone or desktop/laptop, without having to load the whole ragnarok client, a lot of additions could be done like, allowing you to trade, check your inventory, sell, etc... thats why I said, the amount of possibilities that could be done is enormous and just because I'm pointing out the basic feature of chatting, doesnt means thats gonna be only that (well it will, in the first steps).