I didn't know canvas anti-fingerprinting was so rudimentary. I don't think it increases uniqueness (the noise is different every run) but bypassing it seems trivial: run the thing n times and take the mode. With so little noise, 4 or 5 times should be more than enough.
Huh, it seems it's just my browser that resets the noise every run.
I opened the page in Firefox like the article suggests and I get a different pattern per site and session. That prevents using the noise as a supercookie, I think, if its pattern changes every time cookies are deleted.