Photoshop is, unfortunately, the most comfortable art application out there for a lot of art related workflows. The pattern preview mode allows for painting tiling textures easily (a feature oddly lacking from all competitors--except asperite oddly), the filters are all top notch, the ability to do non-destructive adjustments is insanely useful and not seen anywhere else, and the brush engine is the industry standard. There are a lot of nice things about how Photoshop approaches art that others are missing. The fact that Photoshop can manipulate images as easily as it can create them is what makes it special. Procreate is great for painting, but lacks even 10% of the features Photoshop has. Gimp is a decent photo editor with terrible painting tools.

There is a massive opportunity in the market for Procreate to come out with a desktop version that expands on its functionality, but my theory is that it is probably the #1 iPad selling point for many people and Apple is paying them to keep it iPadOS / iOS only. Some big name Japanese anime studios are now working a big percentage of their workflow on iPads with Procreate.