USB 3.0 LC circuit on shield
A 100nF capacitor might have this type of frequency response: -



As you mentioned, at 1 MHz the impedance is 1.6 ohms but if frequency rises you will reach a point where the capacitor self resonates and becomes inductive and, maybe the ferrite bead is intended to always restrain the net impedance to 200 ohm resistive no matter what frequency of signal might exist between shield and chip?

At much lower frequencies than 1 MHz the ferrite will behave like an inductor with fairly low losses and this may also be a feature desired by the designer.