On my Windows PC it takes GIMP 15 seconds to start and get into a state where I can edit. It loads palettes, initializes and what not, according to the splash screen text. That's too slow, so I never use it for quick image edits like crop, scale or color changes. But that in turn has the effect that I never learn the unusual UI. Which means that for more complex task I avoid it too. Other zero cost tools like the web based Photopea loads super fast and mimics the UI of leading image editing suites. It thus beats GIMP on both quick and easy tasks and more complex tasks.

If it started faster, you still probably would find it a bit unwieldy for crop scale and simple color changes. I wish it did those things better, but on the other hand it seems like it would be appropriate to have a simpler program for quick tasks as well.

And I say this as somebody who rather likes the gimp.