This episode serves as a recap of past events, as well as giving Shinbo and Sumomo some screen time. These types of episodes were common back when episodes were released weekly and couldn't be watched all at once unless you bought the DVD or Blu-ray, which came out much later. They helped save on animation and reminded the audience of the most important events if they started watching the episodes from a later point. These days, this type of format doesn't serve much purpose, unless it's for parody, so you can skip this episode without really missing anything. I must say, though, that Sumomo's need to delete data and free up space is an ingenious way to structure a recap episode.