Should get a phone number too. Shit like that happens. Next time lay down the law to the marketing drones from UX that want to "reduce friction".
Explain carefully so their thick minds will understand that NOBODY is lazy enough to quit subscribing to your service just because you added an additional field to your onboarding.
Which most people would be reluctant to provide because everyone hates sales spam, and what else would a SaaS need your phone number for in regular times (impeding data deletion is a good one)? On HN making a phone number for a signup is regularly criticised.
Explain carefully so their thick minds will understand that NOBODY is lazy enough to quit subscribing to your service just because you added an additional field to your onboarding.