I'm voting Vivienne onto the intellectual list.
Yes for most guys looking for a review or feedback, for some it's basically an ego boost (or killer).
I think for some, myself included, we are looking for feedback either to improve or at least ensure we aren't doing anything that is considered bad / annoying. We always want to have the best time possible and figure if we do all the right things that will happen. We want to avoid the chance of the lady feeling bad, disgusted, irritated, annoyed, unsafe, etc. Remember, what a guy thinks is fine may not be by a lady. For instance, I might think my breath is great after using mouthwash for a few seconds. Meanwhile, the SP thinks it's terrible and there's some food particles since I didn't brush. How many guys only use the mouthwash and think they are good to go?
Most of the advice given by ladies is generic (hygiene, polite, punctual, etc). For some things, there is no grey area - it's fairly black and white. But there are other areas where there is definitely a scale and you may think you are a 10 but you really are a 3. But since many ladies have to be tolerant to maintain clientele (or avoid any negative reviews), most guys are going to be invited back even though the lady only wants you there solely for the money. Is the service going to decline, will she start watching the clock, are you going to get robotic, mechanical, or fake responses?