ssh is probably fine for 99% of things. I use ssh exclusively mostly

The features I load cockpit up for is:

• easier viewing of systemd/journalctl logs. You can click on services and see logs, search them, and so on.
• Partitioning a disk. Nothing too crazy, but I can format a disk, wipe them, via the GUI
• Networking configuration. If you are using networkmanager, cockpit will test the changes, attempt to connect, and then revert the changes if the connection fails (in like 15-30 seconds). This is legitimately insanely useful, I can change the ip address or something, connect via cockpit again, and only have the change stick if it’s actually good. (See also, netplan try from the netplan configuration framework.)

Cockpit also offers a GUI for managing virtual machines (via libvirt) or podman contaniers. So someone else might want that, although I don’t really use that. (virtual machines can be managed remotely via virt-manager over ssh by connecting to qemu+ssh://user@remote-host/system, I manage podman via the terminal).