Back Off the Buddha!
It’s certainly popular, but it is worth noting that PbtA has rarely been used for licensed IP like this to date. I think that it is because there is no generic version of PbtA that you can just slap the IP onto like you can d20, Fate or 2d20. One of its innate features is that it is designed for focussed purpose builds.Definitely a staple at this point, comparable to "let's use D20 for everything", though not quite the same level.
As such, I will be interested to see what Usagi Yojimbo does. If it is a bland iteration of PbtA, that would be pretty awful. However, I am hoping we will something more custom built for the samurai action/adventure of the comics.
The fact that there is no draft of the game or it’s playbooks and yet it has an October 2019 release date isn’t filling me with confidence.