What side are you on?
There were many reasons for the special event to take place. More than anything, the Board and the humans were getting out of these fights was information. They found out exactly what vampires' abilities and blood skills could do. It was also giving them a grasp of their strength as well.
Even if most of the human side had lost their fights quickly, it meant that at least in the future, they could try and prepare countermeasures against such a situation if the vampires were ever to attack and turn on them.
One thing that stood out more than anything was their use of abilities, how it differed from those that the humans had. All of the abilities that the leaders had used so far were not available to humans, and some of them seemed to be quite powerful as well.
Of course, for the Board members in their heads, they were already imagining other humans with these abilities and were trying to figure out ways they could convince the other side for this information.