but my parents still want me to use it as I'm entitled to it because they don't want to queue for ages.
That's been the crux of the debate on here. That's the difference between using the RAP as you are unable to use the normal queue and using RAP for the propose of a free fast track.
What I would say to you @skyscraper is that the RAP is there for your benefit and not that of your parents. You are over the age of 18, so you are now your own person, so the decision should be with you and not your parents whether you are able to use the main queue line or not. Like you say, using the RAP also have it down sides, especially if you like to sit in a different seat to those allocated to RAP users as well as missing out any theme-ing or part of the attraction that a RAP user might bypass.