Interesting. I remember trying a copy of newer Photoshop a few years and being genuinely confused by how layers worked as they've always been part of my flow.
The old versions of photoshop and paint shop pro were heavily layer based and selections were automatically a mask of the current layer as in GIMP so GIMP was easy for me to transfer too at the time.
I also find that intuitive is a relative term. Relative based on your own experience.