Don't know about Beyonce, but it's pretty common for big companies to organize private concerts with big names for their employees. I guess it's a case of just spending enough money to make this happen.
It is pretty commmon in departments such as sales, trading or marketing as incentive to e.g. invite $singer upon hitting the years sales target. Or organize a short holiday, visit to a sports event, fancy dinner, something. Seems to spill over to engineering or the whole company in some places.
As a previous engineer manager this sucks . While sales people get all kinds of bonuses for doing their job. The Engineering team gets a pat in the back because nothing broke down.
Not really related and I don't know about Beyonce, but during the dot com bubble, a company called Pixelton had a party with KISS, Tony Bennett and a reunion of The Who. They went bankrupt.