I hear this argument frequently on this site. When it comes down to it, I agree that we can certainly win the title without HCA. And I'd much rather be healthy for the Playoffs, but slip a little bit in the standings, than have HCA and be broken down.
That being said, I still think HCA is huge, and would be a significant benefit to us. We can beat anyone, anywhere. But what HCA does is enables us to close series out faster. For example, if you have HCA in a series, and win your first two home games, then split on the road, you're up 3-1. At that point, you can close it out at home. If you don't have HCA, and split the first two on the road, and then win both at home, you're still up 3-1. But now you have to try to close the series out on the road. This is much tougher to do, so you're more likely to have to close it out at home in Game 6.
With an older, severely injury-prone team like ours, every game matters. For instance, if we'd been able to close out Miami in 4 last year, or Orlando in 4 or 5, we might have had just enough left in the tank (despite the Perk injury and the "David Stern Special" officiating in Game 7) to finish off the Lakers.
Also, in any series against a great opponent, there's a good chance you'll lose a game at home. If you have HCA, you can lose a game at home, then regain HCA by winning a game on the other team's court. If you don't have HCA (like us against LA last year), it is much tougher to overcome a loss at home, because you have to win two games on the other team's court.