> I don't think that's how Google approaches product development. I was wondering the same, i. e. "what are building shapes actually good for". But if you look at the article's screenshots, i think the obvious answer is: they're simply more fun to look at, and maybe add a certain sense of what a neighbourhood looks like.
Insider perspective: I don't know why building shapes were added specifically, but you can honestly get away with basically justifying a project at Google with "because it would be cool".
There's a lot of reasons you can get away with it: Google has lots of internal tools and resources and data which makes it easy to do cool things, Google is pretty well off and can afford to not be particularly "lean", and Management can justify cool things because cool things are like basic science (as the article points out) and lets you build more cool things and because users like cool things ("magic moments").
So it's very possible that the reason building shapes were added were because someone realized it wouldn't take that much work to do using Google's existing data, machine learning & computer vision research, and computational infrastructure and thought it would be cool, they convinced someone in middle-management it would be cool and a half dozen people worked on it for a year or two.
[It could have also been a calculated, top-down decision and required hundreds of people working for a decade with laser focus; that happens too sometimes, I don't actually know.]