I don't know if it's a fad. Seems they've been popular for a while now. In many ways it seems like an entry for percussion in small rooms where maybe otherwise you'd have none; drummers are picking them up because you can downsize a band to three people to fit in a small space and make that measly pay stretch a little farther. But, like the video showed, there are other ways to create a space-saving percussion kit that give you better sounds for much of the music that gets played in small rooms.
I do think there's a place for it, just like there's a place for congas and other hand percussion. Unfortunately there are lots of people who think banging on a surface is playing, and that's where things go a little south for me. But right now I'm grateful that I have the option of getting together outside with at least one band, even if it's just a cajon, it's good to be playing and I know the cajon is not what we'll have if we ever get back to doing this for real again.