Yes, it's a long-run cost-savings, but if you're hard on your brakes the OEMs can stress crack early in their lifespan, whereas the Giros won't, thus tilting the balance towards the GiroDiscs sooner.
I've done enough work with aluminum to be very wary of steel bolts threading into aluminum, like Porsche's steel caliper bolts threading into the aluminum uprights. If I can put studs in uprights once, and be done with it for the likely life of the car, I'm all-in. But, as you point out, YMMV!Sure I can see the caliper studs are very useful if you are regularly changing pads but for us who are changing maybe every two years or so on relatively new cars I'm not sure if it is necessary.
One brake expert thought that the one-use caliper bolts was "Porsche nonsense". Another place I read that it was more to do with the thread lock that can come on new bolts or for very old cars where they can become seized.
I've also read if you are replacing pads regularly then the removal and reinstallation of the bolts will wear the threads in the uprights, hence the studs, and/or weaken the bolts necessitating replacement, but maybe once in a blue moon is not a problem.