Really cool design, I love the dragging of the bubble to choose a camera.
This is starting to move away from the original value prop of Snapchat. If you can save chat bits, what's the difference in using any messaging service. Also, who usually is taking selfies or is using text message to talk to someone when they want to video chat? During most hours when you're on the go, you send asynchronous media since it's easier to create and digest that content from both parties. This feature won't add to the success that they've seen from their core product, just cause a nice little bump in traffic - not a game changer.