I'm using Bing. For me it's about the quality of search results, and Bing got way better in the last few years, while Google was going progressively worse and worse.
And while I'm willing to give some of my privacy for convenience Microsoft just feels like a lesser of two evils at this point.
To keep thousands of now irrelevant reviews, allow themselves to remonetize content and jumpstart a player base that now has no other choice but to switch.
Hey, remember when you could see more than a single line of text of an article on mobile? Me neither.