I would caution any reader to generalize your statement. Just because you used it at your company to limit abuse, and yes that is a lazy approach and 100% what's going on with Anthropic and most API companies, doesn't mean that every company uses phone number gating for this purpose.

The (probably) most famous example being https://www.eff.org/deeplinks/2019/07/fixed-ftc-orders-faceb...

And it's not enough to say "well we don't use it for that". One, you can't prove it. And two, far more important, in an information leak, by taking and saving the phone number (necessarily, otherwise there's no account gating feature unless you're just giving fake friction), you expose the user to risk of connecting another dot. I would never give my phone number to some rinky dink company.

Now that said, I don't use lazy pejoratively. Products must launch.