Good decision on VW's part.
They are having to get into electric cars so having a race team gives them a way to test and develop. This also gets the word out that VW will offer electic cars.
I heard F1 electic series will run only one car during race soon. So no swapping cars.
This will help push a battery technology and quick change if they are allowed to change during race.
or they can just improve on their eGolf: http://blog.volkswagensantamonica.com/tag/2018-egolf/