From a typical "forum dweller" this seems like an argument to familiarity not quality.
Lets give an example what does Krita call itself? It says
> Krita is a professional FREE and open source painting program. It is made by artists that want to see affordable art tools for everyone.
concept art
texture and matte painters
illustrations and comics
Doesn't sound like what one would use to crop and share screenshots.
Gimp looks more favorable. It is comparatively slow to start 3.7 seconds here. Lets look how challenging it is to make that work. Well there is a crop tool on the main tool box. Mousing over it helpfully notes you can press Shift+c if you want to do it slightly easier. If you don't like the split between export and save and just want it to save and shut up I recommend an addon called save-export-clean and a handy binding in my case just alt+x.
If you find yourself creating a series of screenshots for example for an article or howto or some such instead of taking a screenshot, then opening it in gimp you can from gimp take a screenshot of a window, part of a window, or the entire screen and immediately edit it in gimp. Seems this is pretty suitable.
Maybe you don't actually need any of the things gimp does? Well Kolourpaint is basically a better mspaint and opens in 400ms. It has an obvious selection tool. Select what you like and hit control+t to crop to selection. Control+s to save and your done.
Maybe there is a way to do this with less steps yet? Enter flameshot. Click an icon or hit printscreen and click and drag what you would like to screenshot to the correct size. While you are at it You can do light annotations and optionally open it in an actual editor. You can even with a button share it to imgur if you just want a quick way to show someone something. Want the old behavior of just hitting printscreen saving the screen contents to clipboard no problem bind flameshot full -c
Want the full windows experience bind flameshot full -c to print and open up kolourpaint and hit control+v