This is a tremendous victory, but may not be an ultimate victory. It is certainly binding in preventing the governor from issuing the lockdown completely on his own authority. However, he could get the Republican legislature to agree to some restrictions. Also, local county and city governments could still issue restrictions.
This will actually be an ultimate victory at least in some areas, because many smaller counties with no cases will ease restrictions a lot. Bigger, liberal cities like Milwaukee and Madison will probably issue stringent restrictions, but people will be able to drive to a nearby county where things are open, and the restrictions will start to unravel from there.
After all, Wisconsin's case load and death rate are on the low end, and even that must be mostly in the Milwaukee area. Their statewide death rate is only 72 per million. The rural counties and towns have no need for these restrictions. The pressure in those places to open up will be high.