Float glass tanks have been around in aquaristics for decades. They just weren't called that then because it was the only type of glass ;)
They have a decisive advantage over the white glass tanks that have appeared in recent years: they are cheaper.
On the other hand, they have - due to the higher iron oxide content in the glass - a minimal green tint. That is why they are sometimes called green glass. That is, not specifically our float glass tanks, but all of them.
Most people don't mind that too much. Children who have everything else buy white glass. We have that too.