The thing is that the description method in the Error trait in the stdlib is broken. I can't find the post on the internals.rust-lang.org atm, but the author of Failure has a plan for backwards compatibly fixing it and eventually moving (parts of) failure into the stdlib.

The other thing about Rust error handling is the amount of boilerplate to convert between errors. Error-chain and failure are two iterations on how to deal with it. Failure seems to be the current best practices.