The difficulty is in the details. Small differences lead to bigger differences, like in chaos theory [0] What if the model says this coil needs to be 23.1212722 centimeter? Or two coils need to be 37.1441129 centimeters apart? How do you build that? Mathematics is always much more precise than engineering.

[0] https://en.wikipedia.org/wiki/Edward_Norton_Lorenz#Chaos_the...