There is no way to execute code after a ERC-20 transfer or approval (i.e.
making a payment), so to make an action it is required to send another
transaction and pay GAS twice. ERC1363 makes token payments easier and working
without the use of any other listener. It allows to make a callback after a
transfer or approval in a single transaction.
There are many proposed uses of Ethereum Smart Contracts that can accept ERC-20
payments.
Examples could be: