Magazine moderators have the ability to delete posts in their community (also pin/unpin them) and ban users from their community. I don't think it would take a huge amount of time as a rule - it's just a matter of checking in regularly (I suppose ideally several times a day) to see if there are any moderator actions that need to be taken.
Beyond that, moderators typically play a role in curating content and setting/monitoring community guidelines. But we've been talking about people being appointed solely to carry out the more technical/administrative functions in certain magazines to prevent the recent flood of spam. Ie, people have said they'd be happy to ban spam accounts without necessarily taking on the curation of the magazine in question.