Inkscape is professional quality vector graphics software which runs on. I can’t really tell you how common vector outlines are in the wild, I never really dived deep into the other tools like SAI, PS/Illustrator, Sketchbook that all seem to have vector line tools with various abilities. Procreate FireAlpaca MyPaint Sketchbook Pro Sketch pad ibis Paint X Krita Adobe. I have thought about starting a new vector tool exactly for anime-style line art, and borrow many ideas of blender’s grease pencil, especially the editing tools, but that’s one heck of a project. The freehand path tool optimizes paths to remove all excess control points, so you can edit them better manually, but that pretty much kills the possibility to reproduce pressure/angle/tilt etc. Last but not least, we lack good editing tools for complex paths as created by the calligraphy tool. The calligraphy tool was meant to give some stroke effects following direction and pressure, but it’s rather buggy, and paths still end up as plain vector shapes after saving so you basically loose the editing capabilities. Our nightly builds, both stable and unstable might be a bit buggy for a while.

The freehand path tool gives decent results, but it creates just plain bezier paths, simple solid uniform stroke, so basically you’re getting the same sterile look as in any vector editor.

If you are going to use the Bzier tool, it's actually easier to use with a mouse rather than a graphics tablet. Right now it’s not really feasible to do “proper” line art as vectors in Krita unfortunately. If you want smoother lines and curves in Krita, it's probably better to add a vector layer, and use the Bzier tool instead.

Krita vector art