Additional features, settings, or issues not covered by specific Microsoft Teams categories
MS wants your phone number so when you go over their 'free' limits on the product, they will directly bill your cell account for the usage making it extremely difficult to reverse the charges. Read their usage policy, they have 'waived' their current fee schedule due to covid but do not list when they will reinstate it, so they will be catching loads of people that got used to using the service unaware and cash in huge.
Would you expect anything else from such a company?