That company cares absolutely nothing about privacy. Worse, really--Google regards privacy not just as an outdated but harmless relic that they'll allow you to indulge in if you must, but as an impediment to their business model, to be undermined and worked around in every possible way.
One example: You do some discreet Googling in your browser's private mode and then clear your history and cookies for good measure. You've pretty well covered your tracks, right? Think again. If you had a Google account open--for Gmail, Hangouts, Drive, YouTube, whatever--every one of those searches was quietly logged in your account activity. Did Google tell you they were going to do that? Probably, in the fine print somewhere. Would most of us think to check for such a thing?
It's not that Google wants to get us busted. Most of the company's decision makers probably don't care much what consenting adults do with their money and their tingly bits. They just want to give us a "seamless online experience," and incidentally to maximize their ad revenue. But whatever their motivation, Google is as determined to track me as I am to stay untracked, and they have a lot more money and technical know-how for their agenda than I have for mine.
So I use Outlook for my correspondence in the Playground of the Damned.™ Microsoft may not be up for any ACLU or Electronic Frontier Foundation awards, but they seem to be less obsessively anti-privacy than Google. And since I never use Bing (does anyone?) or the Microsoft browsers, I figure I'm leaving fewer bread crumbs in any one place.