That's one advantage, but socket activation is such a good idea that it's hard to decide what it is "really about": the other main advantages are that your daem

That's one advantage, but socket activation is such a good idea that it's hard to decide what it is "really about": the other main advantages are that your daemons no longer need to contain custom code to open the socket themselves, and as a consequence don't need to start as root if they bind a low port so you can get rid of the privilege-dropping code too, and also if your daemon crashes the socket is still there buffering connection attempts until the daemon restarts. It's really exploiting the fundamental tools that UNIX gives you to the fullest to make things more secure and more robust as well as faster.