As far as I know, we are already there. There are some wallets (web/online wallet) who requires mobile numbers for the construction of their Bitcoin wallet. The users can easily send Bitcoins using a person's mobile number considering that both parties have the same type of wallet and have verified their mobile number to the web wallet. This is very common to some countries that announced their  acceptance of Bitcoin. It is based from the phrase "know your customer" so by connecting the mobile number, they can know who owns the wallet.