Yes, I get that, wiki has a nice lineage graph, but again, if I don't care about all flavors of Linux distributions, why should I care about BSD? How are they different? And how does it really matter in the grand scheme of things?

I mean, if I want to deploy a service on the internet and I need a server, or I want a computer that would work as a weather station around my house, or simply a NAS - I need to pick an OS. At this point I may come to realization that there might be better solutions that my usual desktop system (ie Windows/Mac) and opt for more streamlined solution. But then I have all flavors of Linux. Why is BSD relevant?

Sorry if this sounds stupid, but this questions pops in my head every few years and every time I fail to find the right answer.

One of the main differences from Linux is BSD's separation between the base system and installed applications.

On Ubuntu, Arch, Mint, etc. there is no such distinction. Everything is made of packages, including the base system. You have packages for the kernel, the init system, logging, networking, firmware, etc. These are all versioned independently and whether or not they are considered "essential" is up to the user to decide.

On BSD, the base system is not composed of packages. It is a separate thing, with the kernel, libc, command line utilities all tightly coupled and versioned together. This allows the components to evolve together, with breaking ABI changes that would not be practical in Linux. This makes BSD better for research, which is why things like IPv6, address space randomization, SSH, jails, capabilities were developed there.

Packages are used for applications and are isolated to /usr/local. Dependency and compatibility problems only exist for packages. The base system is always there, always bootable, and you can count on being able to log in to a command line session and use the standard suite of tools. It is sort of like a Linux rescue image, except you boot off it every time.

I ended up on OpenBSD, having gotten frustrated with Windows, Suse, Fedora, FreeBSD and a Chromebook.

I grew to appreciate stability, over time - I don't want to have to fix things after updates, including my tweaks and customizations. I want complete control of my computers. I appreciate a cohesive and well documented system. I want simple and consistent and secure. I don't want the OS to take up more of my time than it needs to.

Perhaps you should consider the BSDs to be like different linux distributions, having their own priorities, pros and cons. Some people don't care. Some do. It's all good, having more options.