Even if artificial lighting and natural lighting were equally efficient you would still have to cover the same number of acres in either solar panels or plants. In other words, the denser your vertical farm the more land it consumes. Clearly vertical farming is meant for some really exotic situations in which you might have access to electricity but are in an environment in which you can't grow the plants you want. That situation would probably be a mars colony or a fallout shelter.
Well, it's more efficient (I forget by which factor). So, if the factor were 2, you would need 1 acre of solar panel for every 2 acre-equivalents of planting space. Since you're okay with going vertical, the acre-equivalent could be much less than an acre. So yeah... electricity being much easier to transport than produce, it would actually make more sense to cover a large part of unpopulated area with solar panels, and then farm in very very small portions of the earth.
From an environmental perspective, this is certainly a 'win'. Reducing the amount of land needed for agriculture is a win to both consumers and the environmentalists and the farmers.
