OpenBSD user since 2009. I have never compiled a package from source.

But they can break the ABI because they do not want to maintain compatibility with old proprietary binaries. It's a source world, in the sense that any software can and will be recompiled if and when needed. That doesn't mean every user has to compile their own system.

The only time I build from source (ports) on FreeBSD is because the package maintainer picked "crappy"[1] options. On OpenBSD, I can generally find the flavor of port that has the options I want. If I cannot I resort to ports.

1) for my definition of crappy, not compiling PostgreSQL support is the most common for me

I've used both, most bsd users have. Prefer packages but ports is useful for custom builds and desktop systems.