End of the day Nikki Bella is a star, and the WWE is going to use her power for all it's worth. Outside of Ronda Rousey and her sister, there is no woman currently in WWE that even comes close to matching Nikki Bella's starpower outside of wrestling. She's not A-list obviously, but she's head and shoulders above everybody else by far. The Bella youtube channel has almost 2,000,000 subscribers. Nikki Bella is the 6th most followed wrestler on social media with 11 million followers behind (not including The Rock) only John Cena, Randy Orton, Sheamus, Daniel Bryan, and Shawn Michaels. The next closest woman to Nikki (other than Brie) is Stephanie with something like 6 mil. She stars in a legit reality show that is now on it's what, 7th season (?) even earning her own spinoff.

Nikki Bella is understandably hated by purist wrestling fans, but WWE would be crazy not to use The Bellas at Evolution considering the influence they have on the young female demographic, many of whom wouldn't normally follow wrestling. As people love to say, WWE is a business. Featuring Nikki Bella in a high-profile match at an all-women's PPV is good business no matter how much it might disgust some people.