This is a strange app.
The basic gist is that it wants to help you deal with photographs, one that has multiple frames of a single shot, so it caters to a very specific need of a user: a photographer who often shoots with burst mode, i.e. sports, runway; paparazzi’s, simply those who loves pressing the shutter button.
My quick run suggests that the detection engine is solid, it did not crash and it runs pretty fast on my MacBook Pro. The workflow, heavily relying on your clicks, does not seem to represent well what the app is capable of, e.g. clicking an image opens it in preview, putting a photo into a box doesn’t proceed to the next pair of photos, and pressing tab or the arrow keys does not do anything too — not so great if you’re dealing with hundreds of photos.