The main reason is I've always liked the comic style rather than CG. It's just my personal taste. Also, I do not have the hardware to render high-quality scenes and the necessary skills or assets to do the minor details in CG.
So I use my half-baked render scenes, put things together and add hand-drawn details. The lines improve the contrast of low resolution renders I'm forced to make due to hardware limitations. It's not a one-click filter and takes more time and work than just doing 3D renders.
Using the comic looks and lowered clarity of the image, it's possible to include hand-drawn details without looking out of the place. For example, hand-drawn semen on a realistic-looking CG scene would look pretty bad.
So it's a style born of personal preference, necessity, and improvisation. And as I explained, unfortunately, there are no rendered, complete scenes without the comic look to provide you that option. My apologies.