Well, I'm slow. but coming to grips with Plugin Network Activate, and Theme Network Enable was a bit confusing.
So if you want to restrict a plugin to the network account, choose Network Activate.
If you want to allow access to a theme to you entire network, Choose Network Enable.
I would suggest finding one term that means the same thing. Network Enable is good...yeah, turn it on for the entire Network. Disable and its not available to the network. Would that work...what did miss.
There must be some better terminology available to make this more clear.