I treat every client equally in the core things: who I agree to represent, which listings and opportunities I surface, and the standard of care behind the work. A five hundred thousand dollar deal gets the same diligence rigor as a five million dollar deal. Everyone gets the same honesty about material facts, the same prompt and fair presentation of offers, the same confidentiality, and the same transparent fee structure. Nobody gets steered, and nobody gets a thinner analysis because they are smaller.
Is it for my benefit or theirs? Both, but I would say the question is a false choice. It protects them because they get honest, competent representation. It protects me because one Fair Housing or ethics violation can cost me my license. But the real answer is that if you only do it because it pays, you will cut the corner when no one is watching, and that is exactly when it matters most. So I do it because that is who I am as a professional, and the benefit to me follows on its own.