The other poster is not saying otherwise, though. They're just saying that "hi-def" formats, while technically unnecessary for end-user listening, are often the only way to obtain a decently-mastered recording.

There's no technical reason for things to be that way. But that's how things are.

It's sort of like buying a new car. You want the more powerful engine? Well then you also have to buy the package with heated seats, the moonroof, and the fog lights. There's no technical reason for it, but that's the only way they'll sell it to you.