Having bought/sold a few properties, the value proposition that real estate agents try to offer are in terms of providing advice regarding the transaction.
Most agents can't really give you good advice whether this is a good financial investment, and -- in my experience -- may not even have a good enough judgement to tell you whether the area is good, the market timing is appropriate, etc.
Given that all they do -- in my eyes -- is provide advice on the contract, they're overpaid. Mind you, a lawyer needs to review everything anyway.