A few times I have been in the middle of driving, and Google has suddenly said "We have found an alternative route that is two minutes faster - if would like to keep the original route, then tap the cancel button." Which is soliciting people to break the law. And the alternative route is invariably a stupid one.
Truly amazing that it was allowed to cover the map real estate. If it was a dedicated portion of the screen that might show ads, I guess it would be better?