It creates a cost for spammers. They have to have an account with a Telco, which isn’t free, which in a lot of countries comes with some sort of National ID to register. That’s the reason.

And when making hundreds of billions of dollars off of the ‘woke’ crowd that subscribes to the ‘building a better tomorrow’ ideal, turning into an ignorant and unrepentant fascist piece of shit is a good way to erode market share for free, if you exclude the $46 Billion USD social media site purchase, which is now worth essentially nothing.