For various math reasons you only get consistent systems with 2^n dimensions, so after complex you get quaternions with 4, then the next one that works is 8, then 16, etc. They become less useful because you lose various useful features, like you lose commutabiliy with quaternions (eg ab != ba), and every time you double you lose more things.
I think the thing everyone is forgetting is that valve isn’t stupid, there’s no way they didn’t realize you could work around accepting the (legally unenforcable) NDA, and it’s open invite.
Valve 100% knows that keeping it “secret” is good for hype and was expecting this to happen at any time, and the nominal ban was expected, but nobody is gonna get sued either.
More people are talking about Valve’s “secret” new game because of this than would be if they openly announced it.