It pulls itself along the cables rather than using a propeller, yes, but the motor that's doing the pulling is on the ferry rather than on the shore.

To answer GP's question: I don't know, but given that this was a retrofit of an existing diesel-powered ferry I could guess that this was the cheaper way of doing it.

Yes, but the propulsion is on the boat rather than at shoreside like OP suggested (ie the cables are static)

The point is that on the current system motors which are powered by the electric cable are on the ferry, so it uses propellers to move. The proposed alternative is to use steel cables (which are already present) without any electric ones to pull the ferry, such system should be more efficient power-wise and easier to service.

This is why hn needs a downvote button LOL