Because every other release is a memory black hole that makes my laptop lift off from the madly spinning ventilators 60 seconds after launching the browser. It’s been like that for a decade or more. That is why I’m not using FF, and on Opera as default browser (as well as TOR).
It's #Foxtober. Why aren't you using Firefox? Seriously, why not? It's not run by a giant corporation. It's got a cool community. It promotes browser diversity.