Well, that was...what the fuck
It was dumb, but crazy fun though.
I'm glad they finally made explicit what we've known for a while, that the show tends to treat Spike as the idiot sidekick. Alas, I don't expect any long-term growth from this but at least we got an episode that addressed it.
I lost it at the almost-Powerpuff Girls reference at the end. "And once more, the day is saved by....THE POW- *gets sucked back into the real world*"
Agreed. The clumsy handling of the comic keeps this from an "A" for me; it raises too many problems about the rules of magic and commerce in the pony universe all for the sake of a single throwaway episode. The approach they took also weakens the story in a way; like Equestria Girls, the explanation for what's happening seems so outrageous compared with everything else we know about FiM that it sort of feels like the whole episode takes place in a pocket continuity isolated from the rest of the series. Shame.
Personally, I'd been holding out for some kind of Inception-style "shared dream" scenario orchestrated by Luna to teach them not to take Spike for granted; when it was revealed in the previews that the ponies were hanging out in the sisters' old castle, it'd seemed possible.