I don't see the Big South as a step up; that was an odd decision.
The difference may not be perceptible from the perspective of elite power conferences, but there is a difference between the two, in money and visibility.
"Last week, Hampton announced it would join
the more visible and wealthier Big South Conference in July 2018, a change intended to raise the athletic profile of one of the most academically successful historically black colleges and universities. News reports indicated that the university has been in talks with the Big South for years, and Hampton's president, William Harvey, has been characterized as long wanting to advance the profile of Hampton athletics and the institution over all."
An interesting article that touches on the reactions and motivations behind the move:
Hampton’s move to the Big South will affect the historically black Mid-Eastern Athletic Conference.
www.insidehighered.com
To be sure, it was controversial.