This is another great idea, which i immediately started to use. It's looking quite discreet, not disturbing at all, & we can control the amount of visibility in the prefs. But i find many folders, which still have the old relative size column, which is not needed anymore.
I could look through all the places here, to turn them off, or, if that makes sense, we could have an option to avoid the double display of those bars, if we globally use the new integrated bars.