On top of that, Bing’s deep search feature has proven to be genuinely useful
Not because "privacy:", not because "tracking", but because malicious ads exist, and you'll click on one eventually.
This is even more true for less technical family members.
This is a neat feature, I used browserosaurus for a similar behaviour, but also that means I have multiple browsers open, one basically for each profile.
Running those same specific queries now, the Google results are as bad or worse than Bing's results at the time, and Bing now frequently gets the results that Google did at the time. But my everyday experience is still that Google gives generally better results than Bing / DDG.
That's pretty unsound logic for two reasons. One is that it's not very likely that SEO optimization for different mainstream search engines requires any more effort than for one, secondly Bings ~5% market share is what, tens of millions of people still? If nobody games it you're leaving free money on the floor, and internet scammers are hyper competitive.
But I'm mostly searching for tech stuff. Local content, or answering questions, google is better.