This seems like a very interesting new way of sharing pictures, the only thing I'm "worried" about, is how the images will be shared, will it turn into a .gif when you share it online? If not, will it then just be possible to see the images with the actual app installed on your device, or through an online login on their site? Either that or it'll end up as a video format.
Surely it's a cool and innovative way of capturing stuff, but when/if the images can't be seen as a file on a computer, I don't think it'll be a hit.
Say you've captured an amazing moment, and then you want to share it with someone, maybe your parents or a friend, that doesn't have the app installed, how will they be able to see it? 1. Download app, 2. Log in, 3. Open link again.
I may be overthinking it, but to be a hit (not to mention being a competitor of Instagram) it needs to be SIMPLE, because that's what people understand (most people anyway). With instagram you take a picture, edit it if you like, and there you have a .jpeg that can be stored on your computer or shared.