Without knowing too much about LightSail, the answer is likely due to cost. It is probably much cheaper to buy a bunch of lead-acid or li-ion batteries and put

Without knowing too much about LightSail, the answer is likely due to cost. It is probably much cheaper to buy a bunch of lead-acid or li-ion batteries and put those in your backyard. It is not trivial to put huge steel tanks in the ground and keep air compressors and generators running smoothly over many years. This can change with time though.