My father in law works on this project and he gave this context, fyi:

“This is an all-electric propulsion technology demonstrator. Electric propulsors over the wing are used for landing and takeoff. Otherwise, they are shutdown/stowed and aircraft flies with wing tip propulsors only. I have covered this technology in my Future Propulsion book”

So it sounds like it’s to make takeoff more efficient, but it’s not a 100% electric solution.