Those systems tend to make sense in large parkades with multiple routes of travel in order to direct vehicles to the closest spot.
Most of our parkades only have one direction of travel (apart from the lower level - and that's sort of addressed with the "level full" sign - at least at View Street). Otherwise you just drive the same path as everyone else until you find an open spot.
Not sure it's worth the cost/benefit for our relatively smaller parkades. Are you willing to pay a bit more for parking to cover the cost of installation to have a green light over the first open space?
It's neat, but doesn't really pass the $$ test.