To be more precise, it is the language that makes error-as-values so easy that it actually strays over into "as easy to forget about errors as exception-based handling".

You can successfully build huge chains of code that are just blindly passing errors up without adding any context about where they happened or anything in a way that even Rust can't compete with.

Haskell mitigates this issue by also having one of the more clever ways of dealing with errors, if you start getting into monad transformers or some of the advanced stuff, so it's not all bad. But it definitely can make it so easy to "handle" errors that you just forget about them.