These are two very different things. vscode.dev runs fully locally. It accesses files from your local disk, and doesn't need a network connection (after initial setup/asset caching).
code-server requires the backing server to be available at all times, and all editor features are pulled from the server via a websocket connection. You can pause and resume whatever you were doing from a different device.
code-server requires the backing server to be available at all times, and all editor features are pulled from the server via a websocket connection. You can pause and resume whatever you were doing from a different device.