The thing is absolutely NOT necessary, but if you often play and want to get the maximum, then it's definitely worth it, I personally am very pleased with the purchase. If it lasts me like my Xbox 360 controller for more than ten years, it will be just fine.
Some pros:
Excellent quality materials, feels like the premium product that this gamepad is, even smells great! Built-in battery, charger included, excellent case, interchangeable sticks and cross, very convenient, the ability to customize eSee full review