I have it and it's interesting, but I don't use it much... It bothers me how you can't delete frames. You can erase the whole canvas if you mess up, but you can't delete the frame itself... idunno. it's good for people who like to animate (obviously)
I've made a couple little Flipnotes, and it's surprisingly well made. Its not like you can make masterpieces on it, but its pretty nifty. Also, its extremely nostalgic because I used to make them on my friend's DSi YEARS ago. Here's one I made ^-^ https://www.youtube.com/watch?v=RlwCn_RGxqk