Earlier quoted context omitted.
Devil's advocate for a moment... the definition of a broker is "a person who buys and sells goods or assets for others," or it can mean to "arrange or negotiate" a deal or plan. How is a miner not a broker then? They accept transactions and then place them on a blockchain by performing some kind of work. Sure, at the moment few if any cryptos are definitely securities, but what is going to happen when a company creat…
Miners never have custodial control of the funds in those transactions. They are much more like auditors or accountants than brokers.
They are facilitating a transaction. They can choose to accept or reject a transaction. In this capacity, they are most similar to a broker-dealer.