I guess you can call it that. You can start it on all your devices (e.g. laptop, PC, phone, tablet, Docker containers, etc.) and it will assign a fixed IP to each of them. Using this fixed IP all those devices are able to communicate securely with each other, no matter where those devices are located at the moment. Tailscale discovers the fastest, direct route between each device and routes the packages accordingly.

Example: Start it on all your devices and you can always access the shared files from your PC at home on your phone or tablet, no matter where you are. If you happen to be at home, no packages will be sent over your internet connection (so you can easily use it to stream 4k movies for example), but the way to access those files is always the same (fixed IP) and always secure.

An additional advantage of Wireguard (which is used behind the scenes) is that it maintains a strict mapping of IP addresses and identities. Therefore, you can usually restrict access to services by IP (instead of using TLS certificates or complicated authentication mechanisms).