Here's an interesting observation: Out of the 5 episodes featuring Daring Do, (Read it and Weep, Daring Don't, Stranger Than Fan Fiction, Daring Done?, and this episode Daring Doubt), the ones with Daring's name in it has Daring herself realize something.
In Read It and Weep, Daring Do was still considered fictional and it was more about Rainbow Dash trying to hide the fact she likes reading. The lesson there was to try some new things.
In Daring Don't, when Daring Do is revealed to be a real pony, Rainbow wanted to help her idol. Daring was very reluctant, but in the end, realizes there are some things you just can't do alone, as she and Rainbow had to work together to prevent a curse.
In Stranger Than Fan Fiction, Daring herself really doesn't learn anything and only bail Rainbow Dash and Quibble Pants out. The lesson there was that Different people can like the same thing for different reasons and aspects of it, like Rainbow preferring the action in Daring Do while Quibble Pants prefers the puzzles, and that's fine.
In Daring Done, the trope called Hero Insurance, where heroes usually are excused from paying for the damages done to the city while fighting the bad guys, is deconstructed. Even without Caballeron trying to ruin Daring's reputation, the townspeople hated Daring for destroying a beloved statue while fighting off a threat. The hotel manager even banned Daring because she skipped out on her bill and Caballeron's men followed Daring and ended up wrecking the place. Once Daring realized the damages she caused, she decided to have some of her book royalties pay for the damages.
And finally, in this episode Daring Doubt,