Pros and cons like nearly every design change, even a seeming disadvantage such as rotating mass can sometimes provide an advantage in certain situations - the gyro effects could provide forces the rider could utilise for either stability or indeed for the opposite - bicycle attitude adjustments.
It's not my natural inclination to buy into the 'latest and greatest' however it will be interesting to see if this brings widespread advantages in competition (likely it's daft for most normal people though)!
