This doesn't make sense because we can buy and sell crypto from Coinbase, Uphold, even Cash app right from our phones. We buy crypto and send crypto, and that h

This doesn't make sense because we can buy and sell crypto from Coinbase, Uphold, even Cash app right from our phones. We buy crypto and send crypto, and that has its own fees associated with it. Why does apple allow any app that support buying and selling crypto?