@dicksocrates: No I get it. In this setup, you're right. But with a single 16gb all in one download, this won't be an issue.
No, my understanding is that it will still have the same issue. The point is that the read speed from the HDD is too slow, thus the result is noticeable pop-in. By using the play disc AND the HDD, they get maximum HDD read speed in addition to the DVD read speed, thus avoiding some pop-in. By having it all in one 16GB download, you still have the same HDD read speed limitation, thus pop-in.