Firefox extensions are human-reviewed. Unfortunately Chrome's aren't unless their automated system detects something so for Chrome these concerns are more valid.
This may be outdated, and Google might have improved the process, but the problem I found is that trying to report the extension didn't seem to have any effect.
I had an experience awhile ago where I found a Chrome extension that was inserting its own ads among Google search results. It was subtle enough that most people probably would never notice it happening, inserting an ad in a place where you would expect Google display an ad in results.
https://developer.mozilla.org/en-US/Add-ons/AMO/Policy/Revie...