The benefit is it will be easier to stop spamming, since Google requires a valid phone number for every new registration. But I'm not sure what percent of people do not even have a Google account and not willing to create one.
Most non-US users. Many tech savvy US users. (Biased answer from tech savvy us citizen.)
Even with an account, I would absolutely not use it for 3rd party auth. The perception of Google with normal people is still good, but it has sharply shifted with techies. It is only a matter of time before it becomes a liability.
Sample size of one, and all opinion. Take with a nicely proportioned grain of salt. As you should any and all responses.
Highly depends on what your site is. If you're making tools for an industry where everyone runs on Google business accounts it'll be different than if you make something for a general international market, something where people do not want to link their real identity, ...
Personally, your thing would have to be really important or deeply integrated with Google for me to use Google login.
On HN you'll get a lopsided response to this because smart guys think Google is evil.
I'm not that smart, so I think Google is far more trustworthy than the other sharks out there.
Even though I trust Google more than most, and I don't think using Google auth is a security or privacy risk, and Google auth is almost certainly more secure than bespoke auth, most regular people probably aren't clear on how this works.
They might be reluctant to type in their Google password on what looks to them like a third-party site.
Even with an account, I would absolutely not use it for 3rd party auth. The perception of Google with normal people is still good, but it has sharply shifted with techies. It is only a matter of time before it becomes a liability.
Sample size of one, and all opinion. Take with a nicely proportioned grain of salt. As you should any and all responses.