Neat.
So, you ever get frustrated by builds taking several minutes and test suites running for half hours?
If your answer is "yes", you are probably losing money and don't know it.
If your answer is "no", you are probably losing money and don't know it (or your app is a simple 10KLOC one-man project).
Well I won't lie. I am a solo developer working on some games for iOS and Windows/macOS. Most businesses usually have a dedicated compiling station for very large projects. What about apps like Procreate? Garageband? Microsoft Office? While not as feature complete as some desktop programs, they were all developed with current Mac hardware.
Do you know what I do when I build or let me tests run? Get something to drink, go to the restroom, take a 15 minute break, go to lunch, or let it run at the end of the day when I am done working and check the results tomorrow. If I am still at work, I use that time for programming the next build, or going through my planner.
Why on Earth would you use an iOS device as a developer workstation and/or build server?
Just kill the Mac already and port the toolchain to Windows and Unices.
I agree with that. I would much rather them allow development on Windows instead of iOS. Mostly because Visual Studio on Windows + Resharper is just so good.