Heads come in all sizes and shapes.
The HP Reverb gave me headaches within 10mins of playing due to the small sweetspot in the middle, other people had no issues with it because their IPD was smaller. Same goes for weight distribution, nose sizes, light leaks and more.

I don't think it's a hassle, more a service to get it customized/dialed in for a unique head.
They pay a nice chunk of money for it, Apple can't have anyone badmouthing it because they just sold a "one size fits all" model.