Yes, Apple subscriptions are a reliable way to signup for HBO or Showtime to binge-watch a specific show. Signup and immediately cancel the subscription, that gives you 30 days to watch. No further payment management actions needed.
It is funny that if you sign up for a 7 day free trial of Apple TV+ that if you cancel immediately before the end of the 7 days your trial is up immediately as well.
But that's a free trial. If you sign up for an Apple TV+ subscription and immediately cancel, it does the same thing as any other subscription.
Free trial is a bit different then what the parent was describing though. Which is paying for a month and turning off auto-renew effectively.