How well would this scale with larger organizations that are not able to take a day off just to throw a party? How regularly are parties held? If there are too many, employees may not take the job seriously. A whole day seems like it may take up too much time and may end up setting the organization behind.
What if there is a situation where there are multiple people that all equally deserve the recognition? How would you go about that? If you were only able to select one individual, another individual who thinks they deserved recognition may be hurt if they did not win, which may make their day worse. Adding multiple winners is a possible solution but would that decrease the value of the award?