Yes, it's there to keep water and road debris out of the engine, it's electronics and it's moving components

Haven't had mine on under my 2001 jetta for several years now. Drive across country to Ont every year with it too. However it is there to protect the engine compartment of moisture and road grime. Also with low ground clearance, it protects the oil pan from rocks and debris. It is your preferance....but a couple hundred dollars for an alluminum belly pan can save you thousands of $$$$$$$$$$$$$$$$$$$$$ in repairs later .