Yes that's the whole point the building club villain was in a flex theater which means everything that goes in there is not long term.
Club Villain has actually been happening for years as a corporate party event. The offer to the general public may have been a test for the future, but the event and the items used were not thrown together for it. I have been and I didn't feel the decorations were sub-Disney at all. Much of the "wall decor" outside the sets and stage was a 360 screen and what a clever move as it changes with each event.
I actually loved the decorations and the atmosphere it all created, but all three CM's we talked to pointed out that it was not what they wanted to have for a permanent showcase. For example, the projection at the top of the walls is supposed to be changed to some sort of fixture that they can put up and take down as needed for different shows; something that is held in place by heavy duty hooks on the walls or something, I guess. By what they said, I have to assume that each different show or party will have it's own decorations that can be put on these hooks (or whatever they use) that will make it seem as if the decorations are permanent and the building was created to house that specific show. They want it to be temporary, but not look temporary.
Here is a picture where you can see the wall projection:

They want that to look like a permanent part of the building.
They said this is to have a more permanent look as well (The DJ area):
I have to say that my favorite decorations were the "apple" (I'm considering how to get one of my own to host parties in our garage; I'm sure our adult friends would love it as much as the kid ones) and the skull candles that line the stage. But really, the whole show was great and the sets for the meet & greets were top notch; very detailed and very authentic. The food was really good too. We aren't huge drinkers, so we tried all of the special drinks but didn't really like any except the Cursed Violet. We loved the whole show and really hope they bring it back so we can bring our DD1 when she turns 13.
More pics:

Cruella was our favorite! She was fabulous; we went to see her a couple of times. Pocket, Sleeve and Handbag were sniffing around her set as well, lol. I had a Cuella inspired hair clip that I wore when I saw her.

Maleficent was ... scary; very much in character. We saw her for less than 2 minutes. I showed her the necklace I made with the dragon on it, and she said the dragon should look like her.

Queen of Hearts is a great addition to the line-up! She spent loads of time with us and didn't rush anyone in her line. I made a fan using oversized playing cards and she liked it so much, I let her keep it ... and she brought it on the floor with her during the final dance number and teased the other ladies by waving it in their faces, lol.

The Evil Queen was very haughty, but courteous. I made a poisoned apple to use as a prop and she said it was ok for a first try, but next time I have to try harder. Loved her!
Again, I'm not sure how they are going to accomplish this, but that is what we were told.