If I am the sales clerk, I will just sell what the customer wants as the top priority. It doesn't have to be the 100% right one. Cuz either you lose a sale when you giving advice to a clueless customer or end up argument potentially. It's not good for health for both sides. If they ask what Casey Neistat use, Google it, answer the customer. Let the customer make the decision if they want that particular model.
Although I know if you are real camera professional, you may totally disagree with customer's clueless opinion and choice. And you can make probably the straight line answer as the best for money and value to your customers. From my sales experience, every time I try to help a clueless customer to help them choose the 10-0% right product in the best value, more than 50% time the customers were thinking I was doing something to take advantage from them. (Me: WTF!!!!) and I could lose sales from that. Not good for the business. So now, if customers want something specific, I will sell it exactly what they want.