Why not both? SolarCity (now Tesla) had solar panels that looks like roof tiles. There's a lot of roof space in any town, it makes sense to use that instead of use up land (that could be used for housing or agriculture) for solar power generation.
But it can be all of the above, too. More energy produced is not going to go to waste, and there's plenty of unusable areas like deserts where solar electricity can be generated in various ways.
But it can be all of the above, too. More energy produced is not going to go to waste, and there's plenty of unusable areas like deserts where solar electricity can be generated in various ways.