As per the original question, would I allow a dealer of anything to pick something out for me the answer is yes but not without education and a bit of research.
Look at this example:
Lets say you wanted to drink some some high end Vodka, or Scotch you could go to a high end spirits shop and then you could experience three possible ways to end your quest:
1: one the store would have a tasting event which would enable you to taste for your self many different spirits which would then be ideal for you to educate your palate and make an educated decision, this is a very unlikely scenario.
2: you can ask an educated salesperson, questions on what to purchase based on having a discourse on what you like and what you don't like based on past experience. Most likely
you will end with something you will like.
3: you purchase any bottle that "looks" good based on reading or advertising or what you have heard about a particular product, you purchase it and hope for the best.
It is no different in purchasing an audio system, if you have a good local dealer then you can go in and get hopefully an education by listening to his or her recommendations and then comparing those recommendations to other possible systems the dealer should have on the sales floor, and then after experience different loudspeakers, amplifiers, and digital or analog front ends the prospective customer will now know exactly the kind of sound which will work for them.