It probably doesn't help to think about it that way when using Photoshop, but it might be a useful mental model for developing Photoshop, or as an example of how a general visual programming language UI might work. Importantly, Photoshop does not give you a bunch of little boxes with arrows crisscrossing everywhere like all the clumsy and disappointing visual programming experiments I've seen.
Maybe "visual programming" is like "AI". Whenever you make something that actually works, it goes by some other name.