There are a few misconceptions here that hopefully can be cleared up.
This isn't paid for by any kind of tax dollars.
The effect was never designed to scare or surprise you. As you approach there are several signs that warn you to expect something on the road ahead, including a gigantic electronic sign that flashes and warns you to slow down. The speed limit is 30 km/h on that block. From a long distance, you can see something in the road well before the 3D effect ever takes shape. Once you can make it out, it slowly goes away as you get closer. Eventually, it disappears as a blob on the road.
Those photos are taken from standing next to it. The driver's perspective is very different.
This was developed simply to help draw more attention to the issue of school zones. Every year we hear the same speech by the cops and school board asking us to slow down. People aren't paying attention.
The buzz this thing has generated is immense-- it's gained international attention. Never has there been more attention drawn towards this issue than in the past few years at least. And if you stand there for a few minutes, you'll see cars slowing right down. That's good stuff.
You could argue the financial cost of one child being struck by a car easily exceeds the cost put into this project. And as mentioned before, none of it was tax dollars.