It's been used on UseNet since at least the early 1990s [0].

I think it comes from a Perry Barlow-esque feeling that Cyberspace is an improvement on the "merely" meat real world (perhaps even a proxy heaven on earth, cf. Platonism). Sometimes it is tongue-in-cheek, other times earnest (I assume for people who have found the real world (and their real bodies) a disappointment.)

[0]: https://www.merriam-webster.com/wordplay/what-is-meatspace.