Agreed, and who implement it knows this but they need your phone for other reasons, to ID you, to sell it to ads companies, to find your other accounts that use

Agreed, and who implement it knows this but they need your phone for other reasons, to ID you, to sell it to ads companies, to find your other accounts that use the same number, among others, but none of them is in the user’s favor. That includes other services that market itself for privacy minded people like Signal.