More importantly, you don't need someone technical to tell if it's an important change. This can easily be signed off by QA, designers, PMs, etc. They can see what it was before, after and what changed and decide if that's OK.

Also, the difference between a wanted visual change and a break is dependent on the change you want. That makes this quite a flexible tool (it's not just "any difference is wrong") that can be used simply and is unlikely to have false negatives (while making it easy to ignore false positives).