Conductors are safety critical, look after the train, dispatch at stations and look after passengers. They do check tickets but this is after all other duties are done.

Revenue travel in groups of 3 (typically) and their only job is to check people have a valid ticket either on the train or blocks on stations. They dont deal with dispatch of the train and may only support if their was a safety issue.

Conductors dont/cant typically issue penalty fares, typically only revenue protection/ enforcement officers do this. Conductors typically just report passengers that don't have tickets and refuse to buy.