It would give the Chromium dev team a massive amount of leverage in directing web standards.
This matters because, on-the-whole, Mozilla's dev teams tend to be much better at writing standards than Google's are; partially because many of the standards Chromium focuses on are prioritized and developed with the intention of being helpful to Google's long-term strategies. There have been multiple instances (html imports spring to mind) where bad decisions were averted purely because Mozilla had the guts to say, "we're not putting that in Firefox, come back when you have a better proposal."
Yes, Chromium is Open Source, but Open Source isn't magic. It's still very much a Google product, designed to increase Google's overall influence over the direction of the web. Unless Mozilla's plan is to literally fork Blink, then having a primarily for-profit mono-culture in charge of what features get fast-tracked and prioritized for browsers is still incredibly harmful.
This matters because, on-the-whole, Mozilla's dev teams tend to be much better at writing standards than Google's are; partially because many of the standards Chromium focuses on are prioritized and developed with the intention of being helpful to Google's long-term strategies. There have been multiple instances (html imports spring to mind) where bad decisions were averted purely because Mozilla had the guts to say, "we're not putting that in Firefox, come back when you have a better proposal."
Yes, Chromium is Open Source, but Open Source isn't magic. It's still very much a Google product, designed to increase Google's overall influence over the direction of the web. Unless Mozilla's plan is to literally fork Blink, then having a primarily for-profit mono-culture in charge of what features get fast-tracked and prioritized for browsers is still incredibly harmful.