Empty Arena matches can actually be pretty entertaining depending on the superstars involved.
The problem is that they eliminate one of the greatest aspects of a pro wrestling match: the crowd.
Whether we always pay attention to it or not, the live crowd plays such a pivotal role in making a match succeed or fail.
If the live crowd sucks, odds are the match won't live up to its expectations. If the live crowd is awesome, it can make a good match seem much better than it actually is.
In Empty Arena matches, however, the two wrestlers involved don't have to worry about this because they have no crowd to play off of. They wrestle in an arena that could fit 15,000 people, but actually has zero.
Most wrestlers would probably say that it's easier to work in front of a massive crowd than in front of no one because they feed off of the crowd's energy and use it to enhance the quality of the match.
Even if the wrestling is good in an Empty Arena match, it just doesn't feel like it because there's no crowd to tell us if that's actually the case.