Firefox, and Chrome to an extent, are powerhouses. They have a great community with awesome and really creative extensions. Safari only just started adding extensions and it shows: apart from the usual ad blocker stuff, there's not much out there.
But Safari is fast and is tied to the OS so well that it's great for just using the browser as a portal to the web. Safari has a menu option that allows me to save quickly to my Downloads folder. I can use the share sheet to send URLs, snippets of info straight to other apps. Also, if I'm crazy into automation, I can set up workflows via Automator for even more efficient text processing.
People champion Firefox as the sole defender of the web, but people often forget that Safari is quite unobtrusive too. Sure, it maybe lacking in pushing the frontiers of web standards, but for the most part, it stays out of your hair too (Firefox has this quirky default homepage that likes you to send these "witty" phrases)