My wife told me that's not unknown way to play guitar. But she doesn't remember if she ever saw play this way on spanish guitar.
She told something about hawaiian or steel guitar or so. I don't understand that :-). This kind of instrument was always cryptic to me.

It's uncommon but not unheard of ... blind blues player Jeff Healey performed this way:
https://youtube.com/watch?v=MJh3KaIKDAw%26fs%3D1%26source%3Duds%26autoplay%3D1