They're not the same.

Krita is more of a painting application akin to Illustrator, whereas GIMP is more of a Photoshop-like editor.

Also, work on GIMP 3.0[1] continues, but there's not enough people working on it, so it takes a while.

1 - https://www.gimp.org/news/2016/07/13/gimp-2-9-4-released

Adobe Illustrator is not a paint application. It's a graphic design application.

Corel Painter is a digital paint application. [0]

Usage differences between these two programs is huge.

Usually paint programs lack filters, but specialize in brush macros, biasing behavior in favor of starting with a blank drawing areas.

Meanwhile image manipulation programs pretty much have a configurable airbrush and replicate some dark room techniques, and possess a rich filter library, biasing behavior in favor of altering and layering existing content together, after the original creative process.

[0] http://www.corel.com/

While I'd agree that GIMP and Krita are not same, I think Krita is still closer to GIMP than Illustrator, Ai being a vector editor.

Meanwhile, though probably known to most of the HN crowd it's also worth mentioning Inkscape which is a FOSS alternative to Illustrator of good quality.

I agree with that. Some things are a bit different, like PS -> GIMP, but once I had the basic equivalents down, I found it a great tool.

Isn't Krita quite different from GIMP?

I haven't used Krita but I've watched some videos about it previously and my impression has been that Krita is more like Corel Painter whereas GIMP is like Photoshop.

IOW, whether Krita is "better" than GIMP might depend heavily on what you are looking to do. If Krita is like I think it is then it would be a much better application for digital painting than what GIMP is, while for photo manipulation GIMP would be much better.

I haven't tried either in depth, but AFAIK GIMP targets the image manipulation space, while Krita targets the painting space. Of course the will be some overlap, but I think both are the best in their respective niches.