Is it silly? You'd have to calculate the amount of CO2 sequestered by the destroyed woodland vs the amount output over time by whatever fossil fuel power generation could be replaced by the solar panels. I certainly don't know off the top of my head. Of course it would make much more sense to use already cleared land still - but maybe uncleared forest is much cheaper or something.
It's just way more efficient and uncomplicated to build large scale than to build a large number of small scale stuff. This shouldn't be surprising.