Reason #6. If you've seen one hologram, you've essentially seen them all.
All of the holograms that we've seen so far have essentially moved the same. They're sort of life-like but also not, if that makes sense. The creators of them are able to install a few mannerisms to try and differentiate them from one another. But for the most part, they all had the same basic moves. So unless someone can come up with a way to advance the technology behind them, you can pretty much imagine what a hologram of an artist would look like performing without actually watching it perform.
Photo Credit: Billboard