As far as I know, nowadays, all Bitcoin users can easily send, receive and trade Bitcoins on their phones with the internet. We only need to copy and paste the wallet address or scan qr code and then execute the transaction, it is simple. If BTC is connected to a mobile phone number, I think it is also simple and convenient for Bitcoin trading. However, a big problem is security. If you connect Bitcoin to a cell phone number, your level of security and anonymity is likely to be gone, this is in contrast to the nature of Bitcoin.