this actually isn't bad advice for idiots. so if you're an idiot, by all means it's probably better to ask someone, "how'd you like it if" rather than build it and see. As a great example, everyone knows people like battery life. So if you're an idiot, a great question to ask your customers might be, 'How'd you like it if we made a giant battery, like a car battery, that you can take along as an external battery booster for your next Samsung, so that you can just have it connected and have 72 days of life. It would be deep discharge, so that you have hundreds or thousands of cycles." Why did I use this example? Because only an idiot would ask any customers this. It's idiotic. But if you're the kind of idiot who would make that - then by all means!
ask them.
On the other hand, steve jobs didn't need to ask his customers how they'd like an iphone - he told them why they'll like it.