I'm an artist who's been using Adobe Illustrator as her primary medium for thirteen years. Here's some reasons why my site is still serving up tons of bitmap images:
- Any interesting vector image will be a much larger file as an svg than a web-res png/gif/jpg.
- Sophisticated effects in AI can get lost in the transition to SVG. I don't know if this is AI's fault, SVG's lack of support, or the fault of the various things rendering the SVG, and the first point leaves me disinterested in experimenting.
That said, I have been playing with using web fonts for sets of simple images.
Also, most of my artist friends are completely baffled by AI; they prefer bitmap programs like Photoshop, Sai, or Artrage.