◐ These special episodes are part of this spin-off series' fan service. They are short comedic sequences mostly revolving around Ilya and the members of her household. They do not play around the Mahou shoujo persona (or the magical world in general) that our 4 protagonistic female characters assume, and they usually contain some loli and ecchi elements (e.g. lingerie, sexually suggestive clothing, skirt flipping, pantsu). ◐ Overall, they are more enjoyable than the season itself despite their far shorter runtime. In my view, and based on the ideas that were explored within those 5 episodes, the creators could have easily produced 20min episodes thatwould have been just as entertaining and engaging.
P.S. 1) For a detailed review of the 1st Ilya season, please follow this link (t.ly/IwbO) and give it a thumbs up if it proves to be helpful.
2) For further reviews of the Fate franchise, please take a look at my profile.