Its hard for me to get too excited because we're always picking in the teens.
Rarely do top shelf first round choices even play. A lot back out, especially at the skill positions.
The game is more valuable for evaluating the mid round type players since most of the participants will not be the top layer of the class, which invariably are underclassmen.
This is a good place to find your fourth or fifth round type steal. That good player who gets downgraded for measureables and drill performances at the Combine.
The Jaguars for example stole Telvin Smith a couple of drafts ago and they cited their ability to see how he would work within their defensive scheme was key to the evaluation.
On the opposite side, it can allow you to see what players are coachable and react accordingly.