Dialyzer is easy to intentionally or accidentally mislead, so it's only as good as the quality of human-authored typespecs (which are sometimes absent from major mainstream Hex packages) and the inference is simultaneously more open-ended and unhelpfully precise than most people are accustomed to if they have prior experience with something like Rust or TypeScript. People also frequently struggle to accurately interpret its output.

I still find dialyzer to have non-zero value, but it's not uncontroversial and it's not usefully integrated with the vanilla language tooling. Mix/elixirc is not generally going to throw you a bone if you violated a syntax-correct type spec. It's an opt-in secondary tool and that diminishes its utility a tad.

Also the language is strongly typed and has a compiler which they’re adding more compile-time type checks to.