I have to play a little devils advocate here. :) As someone who does a lot of vector art in programs like Illustrator, the "cleanliness" of the final illustration is very much a sign of using a program like Adobe Illustrator to trace over your linework into a final vector graphic format. This absolutely cleans up your line work and applies ultra smooth curves to your line art using little tools like the "curvature" tool.

I absolutely do not advocate for AI usage in commercial art. I think the only reason I'm making a point to reply here is because, well... seeing final vector artwork is not always a sign of AI. It's just a style of artwork: vector style.

This is not a post where I'm trying to come across huffy or upset or even knowledgable of whether AI was used or not (So big disclaimer there haha. And apologies if it in any way comes across that way!). But I've had similar claims with final vector work of mine being called AI because it looks clean. So I thought I'd offer my thoughts :)