Completely wrong.?
HCA only comes into play if a series goes 7 games. The Jazz didn't play any Game 7's in either of their Finals runs. Maybe they would've beaten Seattle in 1996, I don't know. But those are rare occurrences. Like, can you think of any series in recent history where your opinion is - "The inferior team won this series because they got to play Game 7 at home"?
The largest benefit of a high seed isn't HCA, it's that you generally have an easier overall path to the Finals.
HCA and high seed matters from game 1 on.