There's a whole lot of answers in here saying cooling is impossible or super hard, and that people whose literal job is building satellites haven't thought of this. Or that the people whose literal job is building satellites haven't though about all sorts of other basic stuff like "you can't do maintenance on satellites" or "there's radiation in space" or whatnot.
Yes, they've thought of all those things. Those aren't useful answers
The main advantages continuous high-power solar energy, different regulations being in play (it's "outside the regulatory environment), and in the case of SpaceX it provides synergy with their own rocket launch business. They're creating their own demand, allowing everything to be cheaper in bulk.
Yes, it's to "raise the stock value." Isn't that why companies do anything? Doing a thing that produces value is going to raise the value of the stock of the company doing it.
Here's the usual video I use for this issue, a walk-through of the equations on how things cool in space where Scott Manley runs the numbers and shows that it's perfectly reasonable with a modest radiator panel.
What temperature are you assuming for the radiators? At 80° Celsius (353 Kelvin) they can do 880 watts per square meter. And bear in mind that radiator panels are double-sided, so that makes 1760 watts per square meter of dedicated panel. 80 degrees is what these chips are meant to run at, if you wanted to you could use a heat pump to make the radiator panels even hotter and they'd get much more efficient - according to the Stefan–Boltzmann law thermal radiation goes up proportional to the fourth power of the temperature. Shouldn't be necessary here though.