Usually the currency is tied to the protocol to incentivize people to keep the network up and running - this is essentially what mining is. By helping the netwo

Usually the currency is tied to the protocol to incentivize people to keep the network up and running - this is essentially what mining is. By helping the network to confirm transactions (by mining or staking) you get rewarded with the transaction fees that people pay to make a transfer on the network. Now, there are zero transaction fee protocols like the DAG based IOTA for example (and I think NANO works this way too). In order for your transaction to be confirmed, it has to confirm two previous transactions. So essentially you get no reward other than the fact that your own transaction will be confirmed as well by the next coming transactions.