no-one is a truly expert programmer 100% of the time. Types catch a lot of stupid errors that anyone can make, regardless of skill level. They also localize g

no-one is a truly expert programmer 100% of the time. Types catch a lot of stupid errors that anyone can make, regardless of skill level. They also localize guarantees. If your data has a type, you don't need to understand the full path it took to arrive in your function to be able to work with it. With dynamic types, you can only hope that a value has the type you need unless you explicitly check every time.