I think both Daring Don’t and Power Ponies are different because they’re not in the same place where most of the show was. There’s no point anywhere in the series where Ponyville is like Townsville that needs someone to be saved from danger every few hours or every day. The Mane 6 themselves are technically superheroes, especially in the two-parters. But Ponyville never actually treats them as such all the time. In fact, besides knowing Twilight is a Princess in Season 4. When there isn’t something threatening all of Equestria, they treat the Mane 6 as any normal pony. As a result it feels a bit jarring. Because suddenly Ponyville is obsessed with Superheroes right down to the fan clubs, press attention, and even special commemorations from the Mayor. And yet nowhere else does that happen for the exception of the celebrations after Nightmare Moon, and Discord were defeated. Or Twilight’s coronation. But those being more justified because all of Equestria was saved or it was a special National event. As opposed to one town where for some reason ponies’ lives are in danger at the drop of a dime. Daring Do being real as much as a bit of a conflict it can be, there was actually no indication that she was fictional in the world of Equestria. It was an assumption that was proved false in Daring Don’t. But Daring Do herself still wants to keep the illusion that it’s fictional to most ponies. So to anyone besides the Mane 6’s knowledge, Daring is still fictional even thought she actually is real. And Power Ponies was basically an excuse for the writers to have some fun with some silver-age Comic book silliness. Those who understand how ridiculous the old comics were, will get what Power Ponies was supposed to be. Neither Daring Don’t or Power Ponies do something like making Ponyville into Townsville for only 22 minutes. It’s really only a problem if you’re so invested into the worldbuilding of Equestria. When Mare-Do-Well’s problem had barely anything to do with worldbuilding. Or if it does have worldbuilding, worldbuilding that has barely been mentioned since for the exception of Construction Workers appearing in later episodes, or the dam that broke in the episode coming back in It’s About Time.
Though you know what, personally it doesn't matter to me if something in the show you feel is contrived because, I feel that it's like the equivalent of saying that Daring Do being made real feels out of place in a show that isn't about making references to adventures films and shows. In my opinion, I'd actually give the writers the benefit of the doubt, since for the most part, they know what they're doing. Remember Power Ponies, that was an episode that is also centered on superhero tropes.
