Common to all (capable) image editors
If it's any more powerful than MS paint, there is a huge learning curve. This is universal - it applies to Photoshop, PSP, GIMP, anything else.
If your favourite tool is 'easy', that's because you've already been through that curve with it. I decided to give GIMP a good try a few years ago and haven't looked back since. OK, it has it's quirks (why do I have to export to a jpg when I opened a jpg??) but as with all tools, you get used to the quirks.