campy compatible frames can take normal bearings since you just need the right dimensions? just that there's probably a slight difference in stack height as i observed with the head tube/fork crown gap. but the reason why the standards aren't interchangeable is that campy style bearings go deeper into the frame, so some frames would have material in the head tube blocking the bearing from seating properly?
>The Campagnolo® Hiddenset is a proprietary design, and is basically an integrated-angular contact type without cups. The frame must be compatible with this design for this headset to be used. The bearings cone races do not press into the frame. The frame has a specially machined headtube to accept the bearings. However, this standard is not interchangeable with the Integrated System described above. Adjustment is similar to a conventional threadless headset.https://www.parktool.com/blog/repair-help/headset-standards