for people, like me, who aren't familiar with the acronym: REIT = real estate investment trust

It's not a datacenter REIT. Datacenter REITs don't sell compute. They sell space, power, and cooling in which compute lives.

I get the point the author is trying to make (in that SpaceX's most valuable asset is its compute capacity), but it's not quite the right analogy.

SpaceX is basically Elon's holding company for everything-but-Tesla at this point. If you're betting on SpaceX, you're betting on a conglomerate.