Why not? According to Jason Fried (21 Signals) the organisation learning of how we got somewhere is important to know just why we did what we did, bit also the mistakes we made and the things we learned on the way.
So, if we're looking to develop a new thing, it's important that we understand what worked, what didn't and why. That way we can inform other work in the organisation, so they gain the benefit of our experience.
But we don't learn, because there's no appetite to do that. People say "let's move on, let's not focus on failure", but sharing that failure is critical or the learning is limited.
I'm not overly keen on getting criticism, but I accept that it has to happen in order to improve. Someone who says that you're great all the time isn't helping you grow in the longer term.
So, if something went well, let's hear the feedback of how it could have gone better and if it failed completely, let's hear why that happened too. Don't just sweep it under the carpet!