Think your town should get some of these instead.of planting trees?

I don't think so! How many people have to constantly fight against that very thing in their fish tanks. How much oxygen output does that produce compared to a real tree? Ridiculous!

By the way, aren't those real trees and bushes in the background?

No.  Trees are much prettier and provide housing for birds - these do not.

They are ugly. We have an entire lake full of algae, we don't need tanks of them.

Idiocy. 

Of course not.

Thankfully, we have loads of trees, are quite attached to them and our greenspaces and have no need for supplemental oxygen producers/carbon dioxide absorbers. I presume that is the purpose of the 'liquid trees' pictured. Sadly, there are many urban areas that probably do need them.