Interesting. Back in 2007 my company Motionbox partnered with flipclips.com to sell themed flipbooks very similar to these. Both companies are defunct now.
Demo at a trade show:
https://youtu.be/FIiLsyeAM_I?si=BQHt5Q4Q80y3Il5f
Is that not very dead? I remember trying to order some gifpop stuff back in 2021/22 and they were gone by then. I see the "make your own" page on the site is broken, the blog entries are from 2017 (hover over the bottom of each one). The copyright's updated but I think that's automatic.
I only wanted a couple of images. From what I remember of gifpop, they originally did this using a machine that was intended as a wedding entertainment, guests take a moving selfie and it's printed for you, they repurposed it for selling art gifs - seemed like a great idea.
The fallback - IIRC you could buy preglued lenticular sheets in packs of 50 off amazon, and there was a site explaining how to preprocess your images (but it's not hard)...but it was going to take a bit of effort, I don't even own a printer - so I lost interest.