You don't have to declare types, but they are enforced when you do declare them. I'm not exactly how this is bad. Anyway, you can get into a scenario like you do with Python where type errors occur at runtime if you're not using a typed function.

I'm fine with it, as you might expect from the fact that I'm the author of the linked post.

Julia checks types dynamically. It's type system depends on the evaluation first. So any errors are catched eventually, but not on your desk.

This is only partially true. Almost all types are known at compile time because Julia was designed with static evaluation in mind. Many type errors are caught at compile time.