It’s based on NixOS to provide as much as possible out of the box and declaratively: https, SSO, LDAP, backups, ZFS w/ snapshots, etc.
It’s a competitor to cloud hosting because it packages Vaultwarden and Nextcloud to store most of your data. It does provide more services than that though, home assistant for example.
It’s a competitor to YUNoHost but IMO better (or aims to be) because you can use the building blocks provided by SelfHostBlocks to self-host any packages you want. It’s more of a library than a framework.
It’s a competitor to NAS but better because everything is open source.
It still requires the user to be technical but I’m working on removing that caveat. One of my goals is to allow to install it on your hardware without needing nix or touching the command line.