I love this review of Snapthread by Josh Ginter, especially this paragraph:
These backdrops and Creative Commons music options are, again, very plain and simple. However, the point of the app is to be a quick and easy way to share Live Photos with non-iPhone users and with a little extra pizazz. Snapthread is not designed to replace iMovie, so feel free to export your video after the Live Photo conversion and do more major edits inside iMovie.
Josh really nails what Snapthread is all about: it’s meant to be simple and fast, with a few little extras for those who really want them. I’d absolutely advise people who want more control over music, titles, and other effects to continue editing in a more fully-featured editor like iMovie. I’ll continue to add more editing functions as time goes on, but my intention has always been to compete with super casual apps like Clips rather than bigger apps like iMovie.