Another point that strengths your arguments is that they are going to use mirrors to concentrate light on the panels, and reflective film is much lighter and cheaper than the solar panels.

It means that it's possible to occupy 5x-10x more area in the space with the same amount of solar batteries as on Earth. Yes, the harvest per square meter may be smaller, due to smaller efficiency of mirror->solar panel transition, but the cost/watt may be much smaller.