Although Krita has vector drawing support, it is not good compared to Inkscape, for instance check it out GDQuest's review on the feature:
Krita is really powerful when it comes to hand/free drawing since its strengths come from the raster drawing engine, so if you have a tablet and you have the skills to draw using a pen or something, Krita is the totally go for it option.
Inkscape is focused on vector drawing, it's really powerful when it come to boolean operations, vector effects (like bending, twisting, etc...). It is really powerful making complex shapes out of the box and you just need to arrange them. It is also a powerful solution for designing UI elements, design screens, etc...
If you have the skills for hand drawing and is a good designer as well, I'd say the following:
Use Krita for:
- Characters
- Objects
- Environment
- In-game art (item's thumbnails, character's portraits...)
Use Inkscape for:
- UI elements
- Level Design
- Icons of all sorts (item's icons, menu icons, emojis for in-game [like those Ragnarok emoticons], etc...)
- Anything that needs clean graphics
Although you can use both solutions for the problems presented. As an example I use Inkscape for everything that is graphic related.