The huge size is indeed not neccesary. The ceramics are only there in an attempt to save weight. I have the same disks on the rear, so bias is basically secured to be in the ballpark.
In hindsight, other low-weight good braking options might have been the better solution. But you know how that goes: the you start with a cheap ceramic disk and it kinda evolves from there
The 996 spindles are an alu cast piece, which might save a little weight even more...(if I can find them in GT2/3 form)