Krita has vector layers, but it's not the absolute focus: the purpose of vector layers is adding frames for comic books, text, speech bubbles and the occasional other bit of clipart.
I feel like a number of basic pieces are in place for Krita to be really good for this, but it's not quite all put together and hasn't been expanded out into a really usable form yet.
I think they did a bunch of overhauls a while back (through a Kickstarter) where they specifically rebuilt and beefed up the core vector engine, but if I remember correctly other features ended up getting more votes during the campaign than some of the followup user-facing vector tools/systems they were thinking about, and they ended up prioritizing the other stuff that got more votes.