- There's generally no dependency management, or you're forced into using Cocoapods, and using it in a bad way (binaries in your repo).
- You're at the will of the vendor for additional features (framework, Swift nullability/generics integration, bitcode), and, if they're even available, dependency bumps. This gets really painful. Every time I used a closed-source framework, it ends up being a nightmare.
This is compared to:
- Add line to Cartfile
- carthage update
- A little drag and drop
- Done, future releases will probably Just Work
You might have better luck with people that aren't necessarily "iOS devs", i.e. games, where using closed-source is more common and they might not even be using Xcode.