This company employs about 1000 people and is active in half of Europe, with somewhere around 20 million users of their software. (rough estimates here) The company switched from Google to Microsoft before, and back to Google.
Currently, they also use Google Cloud for hosting, including their proprietary APIs/services like their entity storage.
We even have all kinds of "Google"-branded goodies from these events :)
You thought knowing and maintaing strong password is enough to guarantee access. Well Google disagrees with you.
If migrate to a different country and dont have access to your old number you will be in world of pain.
Getting access to anything is suddenly hell. I explicitly disabled 2FA after encountering this bullshit once. Won’t risk losing my account again.
Personally I've also got it floating around one of my Linux devices with a small program I can run against it to display the codes, which came in handy when I switched phones and forgot to reload the GA app. (Yes, I know that this defeats some of the security of the second factor, with it supposedly being "something you have" that can't be easily reproduced).
I’ve almost lost my Google account twice in less than a year due to Google’s terrible 2FA implementation.
I’ll take my chances thank you.
And "helps making this more efficient" ... well, a tiny bit more. Knowledge is power. Google posesses a lot of knowledge.
But even "only the ads". There are worlds between showing someone random ads, or a highly tailored custom one, made out of all the online and much offline activity of that person.
And knowing allmost all about what a company is doing and controlling their communication is potential valuable in various ways as well.