> I see scan lines (of the NTSC/PAL variety) when I zoom in.

Color vector monitors still have discrete phosphors. You're not seeing discrete scanlines, you're seeing discrete lines of phosphors.

> I also don’t see how this scheme would be less possible with NTSC/PAL.

Vector drawn video games must necessarily be on an all black background. Video games that draw backgrounds and sprites typically illuminate the entire screen. Your character will move around on a colored background. It wouldn't make any sense to do a long exposure on an illuminated background; it would just be a picture of the background with some blurriness where the sprites occasionally were.