For me, who's daily driven FreeBSD in the past, and switched back to it again recently. FreeBSD serves as a refuge from systemd, and the only BSD that is a fairly drop in replacement for linux in terms of software compatibility, as well as the only game in BSD town in terms of support for modern hardware.(though it does significantly lag Linux in this regard still, so YMMV).

As to why I use it over the various systemd free linux distros? Well, there's a couple things. First lot of those distros, like Artix linux say, actually have smaller communities than FreeBSD(I'm guesstimating based on the activity level in their irc channels). The Linux community might be much, much larger than the FreeBSD community, but it's also extremely fragmented.

triggerwarning, hyperbole incoming. Don't bother correcting me, it's a polemic, not a scientific paper

Secondly, for someone like me, who's been using various unix like OSes for two decades, FreeBSD is just a nice, batteries included, well integrated system. Things like jails, Dtrace, ZFS, Bhyve, pf etc. All being in the base install means they're just better integrated with the kernel, and eachother. Most of those things exist for linux, or have equivalents, but they're not all part of the same project. Obviously Dtrace and ZFS originated in Solaris, but they've been made first-class citizens. There's a harmony to FreeBSD that Linux distros lack. Documentation is also very good, all accessible via manpages(no GNU INFO...). And, as I mentioned briefly before. It doesn't have a lot of the cruft that's been added to linux distros over the years(though some of it is available in ports if you want it). In FreeBSD, my experience is actually useful. Things I remember how to do from 5 years ago, 10 years ago, 15 years ago, still work. If I'm on some modern, plug and play linux distro, I have no idea what's going on under the hood any more. All I know is it's not what was going on 5 years ago, which isn't what was going on 10 years ago, which isn't what was going on 15 years ago. The amount of pointless churn going on in the linux space is ridiculous. When I started using linux, what I loved about it was that it was transparent. I could change anything. The system was easy to understand. Yes, it was janky, but it was understandable jank, whereas Windows was janky in an opaque way. 20 years later, Linux is still janky, but nothing is understandable, at least not to my greybeard brain. Systemd takes over a new daemon every distro upgrade. DNS resolving now involves 4 different daemons with 15 different configuration files, there's two display protocols, both broken in different ways, /etc is full of long files written in strange, alien languages, and every file has its own bespoke language. There seems to be 54 different ways to make any change to your system, and all of them are somehow unsatisfactory in a unique way. I just can't, anymore. Enough already.