It takes the same space in the flow as if not transformed, but it will take clicks and other mouse events using the transformed size and position. In your example table, transform:scale(0) will behave like visibility:hidden.
I have always stayed away from scale() whenever avoidable, especially using scale(0) to hide an element caused issues when the element is scaled up again.
Depending on the positioning of the parent and sibling elements, it caused too many reflows and pushed other elements around, too much mental gymnastics for my liking.
It can be useful, just my personal experience.
