Before anyone asks: I am not aware that this has ever been proposed or used somewhere, unfortunately. Quora seem to be set rather ad-hoc almost everywhere, even in quite important “official” rules. I’d be glad if someone finds in-depth sources.
For comparison, these are the alternatives often found:
Even the – objectively bad – participation quorum is not only used in Catalyst, but also in the rules for state- or nation-level referenda.
CIP-1694 up to now includes what I have called “Fixed Margin Quorum”, which is quite okay, but requires a certain level of participation at the lower end and does not allow tight decisions even at 100% participation (might be considered good or bad). And the margin is an arbitrarily set number – like in the other examples.
The reason for the minority < 2×majority² formula is that it is – arguably – the simplest mathematical function allowing decisions even at low participations and approaching no margin requirement at 100% participation.