This is my understanding. Google tout a number of benefits on their plus codes website https://plus.codes/ which I think is trying to claim superiority over alternatives like What3Words. Not mentioned on the site is the benefit that it's part of Google Maps, so most people won't need to install yet another app if they want to have an easier way to refer to a location.

I think Google have had a trial run of this technology around Shoreline Lake, which just happens to be a stone's throw away from their main campus. I noticed this a few weeks ago and thought it was odd they'd managed to get a car onto the paths. Then I noticed the bike helmet:
http://maps.google.com/?ie=UTF8&ll=37.433176,-122.086537&spn=0,359.987683&z=17&layer=c&cbll=37.433197,-122.086733&panoid=Ds8N09-bAtoW_kNY2g348g&cbp=12,32.78,,0,17.17