I don't even understand which part of the tree experience these tanks are supposed to replace. Are they really just there to pick up CO2? Because you can also plant a forest outside the city for that.

You'll miss out on all the other tree benefits, but so you also will with these glass tanks.

People can grow trees. You need a lot more to make one of those contraptions. Hard to control people when they can just grow a plant to do what they need.