So many use cases. It serves as my mail server because it is secure and simple. It serves as my gateway via wireguard to my homelab. It serves as a daily driver on my x220. It is a simple and straightforward operating system. It can 100% serve you as a daily driver even on desktop (excluding maybe running Steam).

But the simplicity also yields stability. Upgrading Arch for example can sometimes backfire. Upgrading OpenBSD? Almost blindly. It just works (tm).