i don’t see why not, but i personally wouldn’t listen to them on there. i don’t have or use spotify, and his airchecks are already on youtube and can easily be listened to on there (that’s what i do).
I wouldn’t listen to only K.K. songs often, but it would be convenient for me to have them on Spotify. I’ve wanted to find a particular song a few times, and having them all on Spotify would be nice.