I currently use an air tag with my Cat which is excellent while I live in a city this would be great for when I visit my parents and have to bring the cat. I don't expect the cat to get out but if it does it would be nice to know that I can track my cat and bring him back home. This would also work wonders with Dogs, as when you get a new dog they often find the holes in fences and then you have to get your daily work getting your dog back. It would still be a workout, but knowing where they've gone without running around in panic looking for them would be great.
I'm super excited to see that it's open-source as well! I'm definitely going to look into this :D