Actually it does make sense. Most Head Coaches aren't the ones the recruits build relationships with on the recruiting trail. It's the assistants and the position coaches that they get a bond with. Since Mack left on his own and by himself. You want to keep a winning staff together which means keeping your recruits. If you hire a new coach, they will bring their own staff. The interim title protects NCCU in case this staff can't function without Jerry Mack. Then they can let them go in good faith having allowed them to try to run the show. Plus you salvage recruiting season by keeping them around.
I expect NCCU also knows that our Coach and their alum has one year left on his contract. If this staff fails, I would imagine they will be making calls to Big Worm at this time next year without having to buy him out of SU. Unless he signs another extension this offseason.