I was expecting it to be inefficient, but after looking into the, the efficiencies are a lot higher than I expected them to be, esp. given that they have a choice about what solar farm to beam to, so can avoid adverse weather. Looks like they could probably get like 50% laser efficiency, 40% system, with a ~500m spot. And 1064-1070nm is 90% clear in good weather.
Solar power in space gets ~40% more W/m2 than on the surface, has zero blocking by clouds, no night, passive solar tracking, no land cost, only one-off permitting costs, low mount costs (minimal structural loading), no weather damage, no dust, and they can beam to wherever they can sell the power for the highest price. Historically it was right-out because of high launch costs, but launch costs are plunging, and could get very low indeed. Also, space solar tech has advanced dramatically in terms of W/kg in the past few decades, and is likely to advance a lot more if this is pursued at scale.
Of course you have radiation, no maintenance, micrometeoroids, launch packing/stress/deployment, beaming, thermal management, and a whole host of other things - one can absolutely not say it'll be cost effective. But at this point, I don't think we can assert any more that it won't be cost effective, either. It's probably about the right time to start working towards giving it a shot.
There's also some fun things you can do with this, like on-demand spot-warming of specific areas and the like. Not visible lighting, mind you, since this is IR (the Soviets once did a small-scale experiment with mirrors to light a town with something like 1% of the sun's light from space)