Well, the Null Object Pattern is clearly the worst of the bunch, since it requires a whole lot of extra code to set up. It also introduces maintenance issues since you need to keep adding methods to it. Basically, it's a horrid idea to use in Swift.

In languages with good type-checking and optional / maybe types (like Swift, Scala, Rust, Haskell, …), the null object pattern seems less useful, because the compiler makes sure you unwrap things in the right places. But the null object pattern seems really useful in languages like Ruby and Python, where attempting to use optionals tends to just replace null object errors with errors from forgetting to unwrap the value.