If you are doing things with Either and using say ...

# arrow

[raulraja]

If you are doing things with Either and using say Deferred from Coroutines now you have to contemplate the case of left and right everywhere somehow but with kinds you don't have to. If you continue down the path of using Either soon you'll end up with a Deferred<Either<Error, A>> and to get to A sanely you are gonna have to resort to EitherT to flatMap through until you get to A