Is streaming about to have a Wordle moment?

It's game time for streaming services: a growing number of streamers are betting on casual games as a way to keep viewers hooked when they've run out of things to watch.

Toronto-based Zone-ify added free casual games to its ad-supported streaming service in June. Last month, close to 70 casual games arrived on Happykids and Fawesome, two ad-supported streaming services run by streaming startup Future Today. And later this year, Netflix is expected to expand its own gaming efforts with what...