Have you looked at the video? by default it doesn't resize 2x it resizes 10x after quite a lot of zoom, and the new lines coincide with the previous major or minor line depending on if you have zoomed in or out, one would have to be very distracted to not notice this. As a grid user I find this friendlier because I don't have to manually choose for each object and at each zoom level what grid size I need. Also let's not forget that in the end the grid is just a guide, constraints are what really matter, so it's usually not a big deal if you occasionally miss click.
Also notice that an auto resizing grid is common behavior in many software out there so a lot of users would find this much more natural than the current behavior where the grid has the same size whether I'm drawing a 2mm circle or 40m x 60m rectangle unless you manually set it for each. Personally this meant that I set a default value for the grid that makes sense for the sizes i usually work with, and whenever I need something bigger or smaller I just disable the grid because it's not worth the hassle.
Either way, this discussion is only relevant when discussing the default setting for the auto resize feature, the benefits of the fundamental changes (which are independent of this feature) and the existence of the auto resize feature itself are basically indisputable.