I don’t thinks so… it’s relatively difficult to get different phone numbers so it’s a good way to limit spam.

Plus in the real world, it’s also a way of separating your identities. I have a work number and personal number, and only attach the work number to business services. Sure, it won’t prevent Google from banning all your accounts but for everyone else it’s a hard barrier to correlating that you are the same person. Added to the fact that my work laptop uses VPN, and I’m pretty sure that sites like GitHub have no idea I have multiple accounts.