gimp is nothing but a hobbyist port of a long-obsolete version of Photoshop.
I would agree, in part.
Last time I played with both, GIMP had somewhat lesser functionality relative to PS's full complement. But, GIMP had added functionality in
different areas. The most noticeable (to this unreformed script-writer) was the ability to use multiple/different scripting tools/langs to automate tasks in GIMP. I recall Script-fu (Scheme), python, and perl as being options.
After a look-see, I see that tcl s also an option and ruby is an experimental option.
To someone who hates repetitive tasks and re-inventing the wheel, using existing scripting languages for in-program automation is a winner.