Just in terms of developing software for the iPhone, it is worth it to go for a Mac. Then there is developing for the Mac. Remember, you can develop for Windows, Android, and Linux on either one.
You speak of the benchmarks being cherry picked, but Intel designs for the benchmarks. The benchmarks are not reality.
I have not been impressed with compile times on Intel chips. Their power consumption is much worse.
But mostly it is the design choices, which has nothing to do with the Intel chips. Apple just makes good design choices --- Except for the Studio Display electrical plug being attached to the monitor, that just bugs me --- But for the most part, excellent choices.
It is like mechanical watches. You pay twice as much for 20% better. The question is how much are you willing to pay for a slightly better Apple. My answer was about $8k of my own money, and about $2.5k of an employer's money. I do not have to pay taxes on the $8k, and do not have to pay anything on the $2.5k.