I guess its more meaningful for people with friends and family in other countries or for group chatting
you can do what most apps do with some sort of native built in app but we still download apps to get a different look, feel or experience
Possibly. I've been using Skype for that, but I can see WhatsApp being a Skype alternative.
I just think WhatsApp isn't the most useful app for the public at large. It has its place, but for most of us it's just like another way to send texts.
I love downloading apps to get a different look, feel, or experience, but not when it requires that I get OTHER people to do the same in order to use it, y'know? Like, I'll try other browsers, other music players, other keyboards (if I were jailbroken), but it's like trying out a different Scrabble game when all your friends are playing Words with Friends. Trying to tell them all to join you on this other app is a PITA.