Swiftz

Assumes familiarity with advanced functional programming concepts like arrows and monoids, which can be alien to Swift developers used to imperative or object-oriented paradigms.

The README details multiple setup methods (Carthage, Git submodules, SPM) with specific steps, which is more complex than simpler dependency management for mainstream libraries.

As a specialized functional library, it has a smaller community compared to popular Swift frameworks, resulting in fewer tutorials, examples, and slower issue resolution.

Persistent data structures and functional abstractions like arrows can introduce runtime overhead, which might not be suitable for performance-critical applications such as games or real-time systems.