We currently make around 1 TW of photovoltaic cells per year, globally. The proposal here is to launch that much to space every 9 hours, complete with attached computers, continuously, from the moon.
edit: Also, this would capture a very trivial percentage of the Sun's power. A few trillionths per year.
Think about it. Elon conjures up a vision of the future where we've managed to increase our solar cell manufacturing capacity by two whole orders of magnitude and have the space launch capability for all of it along with tons and tons of other stuff and the best he comes up with is...GPUs in orbit?
This is essentially the superhero gadget technology problem, where comic books and movies gloss over the the civilization changing implications of some technology the hero invents to punch bad guys harder. Don't get me wrong, the idea of orbiting data centers is kind of cool if we can pull it off. But being able to pull if off implies an ability to do a lot more interesting things. The problem is that this is both wildly overambitious and somehow incredibly myopic at the same time.
This only works so long as the atmosphere being displaced weighs more than the balloon plus the payload. As soon as the air gets thin enough that the weight of the balloon+payload is equal to the weight of the air that would fill the volume of the balloon, then it stops rising. (Or, more likely the balloon rips open because it expanded farther than it could stretch).
Usually, this is really high in the atmosphere, but it's definitely not space.
This is all ignoring that orbit requires going sideways really, really fast (so fast, actually, that it requires falling, but going sideways so fast that the earth curves away and you miss).