I enjoyed the Harry Potter games I've played and have played pretty much every "monster" game that exists (Pokemon, Digimon, DQ: Monsters, Monster Rancher, etc). As a fan, I'm sorry to say I don't see myself being interested in a Fantastic Beasts game. I would love to be proven wrong... maybe it's because I didn't enjoy the movies but I don't hear anyone mention fantastic beasts for any reason, good or otherwise.
The idea of a Steve Irwin running around London catching magical animals should be enough. No need to tie it into the movies or plots.
Niantic already released and sunset a Harry Potter: Wizards Unite.