An upgrade is a suite, or an ocean-view room, something along those lines.

Just like getting upgraded on an airplane, you're getting something because of status that you would otherwise pay quite a bit for. Concierge access isn't an upgrade since that's a basic perk that every Gold/Plat gets. That's akin to getting checked bag fees waived on an airline. Getting a first-class seat? That's an upgrade. Same idea with a hotel. Getting a much better room, not getting the same room but on a floor with a lounge.