One thing I would suspect is they leverage third parties and share your phone number to get back additional known data about you or your interests or other activities which other companies have shared. I think in a way it ends up being a connection point for your data across many places.
If you might ever need to be reached at the number being shared there's always the route of VoIP products like Google Voice (free), or Twilio or MySudo (not free), where one can create virtual numbers for different use cases. In general it's more secure to share a VoIP number anyway since it isn't vulnerable to the same SIM swapping attacks that cell numbers are. I don't know that it's possible to create a Google Voice account without providing a real cell #. One could probably get around that with a burner phone.
Where there is only a short-term need for a reachable number for SMS verification or communication purposes there are services that provide temporary SMS numbers, like mobilesms.io. Because these numbers are recycled frequently, definitely don't use them to register anything important like a bank account or email address.
One thing I would suspect is they leverage third parties and share your phone number to get back additional known data about you or your interests or other activities which other companies have shared. I think in a way it ends up being a connection point for your data across many places.
How do you combat this sort of thing? Besides periodically changing your phone number, of course
If you might ever need to be reached at the number being shared there's always the route of VoIP products like Google Voice (free), or Twilio or MySudo (not free), where one can create virtual numbers for different use cases. In general it's more secure to share a VoIP number anyway since it isn't vulnerable to the same SIM swapping attacks that cell numbers are. I don't know that it's possible to create a Google Voice account without providing a real cell #. One could probably get around that with a burner phone.
Where there is only a short-term need for a reachable number for SMS verification or communication purposes there are services that provide temporary SMS numbers, like mobilesms.io. Because these numbers are recycled frequently, definitely don't use them to register anything important like a bank account or email address.
Do you have any reason to believe this other than "corporations bad"?