DC-PoW or Direct Correlation – Proof of Work, is the work (processing caches for others’ transactions) you are expected to do is equal to the number of coins you hold.
It is not an opt-in, it is a requirement. But, you can delegate your effort to someone else, who is willing to do this for you. By default, this is automatic.
You also are not locking in or burning your coins, you can move them around. In Ethereum’s upcoming PoS switch, you lockup your coins.