Because the harness is in its early form. The more advanced harness in the current time look like Amp:

- Cloud workspace (Orb) and agents.

- Multiple agents with different LLMs and system prompts for different roles (Main, Librarian, Oracle...).

- A universal agent (Puck) for managing the whole workspaces.

- Web app or native app to work from any devices.

- Support subcriptions and API keys.