Thats right, the level of tesselation in games is far less than what is in the heaven benchmark. Despite fermi's power in tesselation, it is quite average in other aspects so you get potentially lower FPS in real games.
I wouldn't worry about tesselation yet. Both Nvidia and ATI suck at it, just that Nvidia sucks less. If you want to drop your frame rates really really quickly for little to no gain in visuals, then tesselation is what you want. Same with ambient occlusions. Maybe a few years down the line when the technology matures we can expect good tesselation.