What does car surveyor do in the claims process?!

Just realized that when an accident happened and during the claim process, the surveyor hired by the insurer does not do anything useful. They just check whether are the damages justifiable and is that damaged part covered by insurer. The car surveyor doesn't even analyzes is the damage really caused by what's written on your statement or third party statement. I really wonder how useful is their role and do they deserved to be paid so much and inflate our insurance premiums and claims amounts. >:(