It is definitely not needed. Higher octane gas doesn't neccesarily mean more power. It can help an engine run smoother. If the engine has computer controlled ignition with knock sensors, it is possible to advance the timing more, or leave it advanced more without the computer pulling out some advance to combat detonation, which the user sees as more power (it's actually not more, it's just not as hindered).
On our bikes, there is no knock sensing ingnition, so you won't see much of a power gain. In my opinion, it is definitely not worth twice the price of regular premium gas.
Try a tank out to see what you think, but more than likely, you'll just be throwing your money away.