Ive played with this now for a half an hour and can only make live photos work if you use one of their default Live Photos. Choosing a live photo of my own just brings up a still image. The concept is good but until I can use my own live photos I certainly didnt need to pay 1.99.
Using their default Live Photos just image is a half a second at best
DennisM99 about Watch Faces - Custom Themes & Live Wallpapers