Maybe giving them your phone number gives Google another signal to catch hackers in another country trying to taking over your Google account. Or a malware server could be prevented from taking over tons of Google accounts? I don't want in abuse, so there are only guesses.
I don't mind giving Google my hone number to keep my data secure, and I'm in the majority, so this is a good thing IMO.
To further lurker456’s point, phone carriers are currently one of the weakest point if you care about security.
I assume you are giving your phone number to a lot of entities already (public administration, HR, service prodivers, delivery etc.). From there a simple phone call to your carrier will be enough to reset your contact dmail, SIM and/or have a new one activated.
You should, because anyone that can compromise your phone will be able to get into your email.
From there it's a small step to reset passwords (SMS 2FA won't help here, as they also have your phone) to all online services you signed up for with that email.
Yes, but you need to weigh that risk against the risk of not having 2FA.
Taking a step back, and responding to the other comment in response to mine as well, I was just speculating. I don't work in abuse, and I'm inclined to trust the Google abuse engineers over myself or random HN commentators to keep my Google account safe.
I don't mind giving Google my hone number to keep my data secure, and I'm in the majority, so this is a good thing IMO.