There used to be an online competition years ago, I think it was called “TheMostSpam.com” or something like that, where you would get a temporary email address and it would track a leaderboard of whose address received the most messages in 24h, a month, and lifetime. Modern email tech rendered it pointless, but back in the days of the simpler internet, it was a fun concept.

The combination of properties 1 and 3 makes it a pure function, which is also useful in compiled or jittable languages because it allows for a variety of optimizations.