From my perspective, Coquese and Beth have similar coaching credentials. Coquese reached a higher level of success as a head coach at a school with strong athletic resources, but then hit a downward spiral after three conference titles. Beth made steady progress at a school with fewer resources. They were both successful assistants at ND.
My guess is that Niele must feel more comfortable with Coquese in a daily working environment. It is interesting to remember that Niele replaced Coquese on Muffet's staff.