DVD/BD Specials. The bane of most of you completionist MAL users. Most are terrible. Some are simply a chore to watch...which is a real shame considering the idea that they are meant to be a bonus candy, icing on the cake exclusive to viewers who are privileged to have the DVD. Fortunately for you, Prisma Illya is the exception.
These Specials don't bring anything new to the table, but fortunately they are drafted and storyboarded like the 4-5 minute anime we see today, in that each one does a nice job of delivering its punchline. The core of which, is typically
fanservice, but as a fan of the Fate multiverse the specials also keep in line what the anime itself did which is make subtle and otherwise not references to the Fate universe, such as Shirou's cooking, Rin in cosplay...well I won't spoil the other easter eggs for you.
Surprisingly or not, the art department stays true to the quality of the series, which was also hit or miss, but it has production quality similar to an actual episode of the show which is refreshing. There are some specials that should have been buried at the drawing board (K-On I'm looking at you) and this is not one of them. Once again, well directed and sounds like a regular episode. Our same tried and true all-star cast is present as well.
Overall, I've generally come to accept that if there's a DVD special out it's probably some gag reel (like Index/Railgun), something poorly constructed and thrown together (like K-On) or generally boring (Tachikoma no Hibi). Instead I was pleasantly surprised by these specials that retain the quality of the anime itself. If you enjoyed the anime, give these a whirl as well.