When stunt riding, the bike is often subjected to extreme angles and high accelerations, which can cause the oil to move away from the oil pick up and create air pockets in the oil pump. This can lead to oil starvation, which can damage the engine. An oil pick up extends the reach of the oil pump, helping to ensure that oil is always available to the pump, even under extreme conditions.
So while not absolutely essential, installing an oil pick up can provide peace of mind and additional protection for your engine when stunt riding.