How many natural habitats will need to be destroyed in order to make artificial leaves useful in any meaningful way?

Natural habitats has been destroyed by agriculture.

In the US 10-20% of agricultural land is used to produce chemicals like starch, sugar or biofuels, if we could use less land to produce these it would be great.

Photovoltaics could be up 100x more efficient in producing these chemicals.

This technology could free agricultural land back to natural habitats.

I'm pretty glad that when we've chopped down all our forests, we'll have mechanical leaves as a backup plan. Having the means to generate enough electricity to take oxygen out of the atmosphere could be useful.