It is interesting but looks more expensive and prone to failure, before even considering that the guide rails could get clogged with debris.
Lots of things are patented without being worthy of actually doing.
If automakers really cared about efficiency they could make minimal changes towards using precision pivot bearings and a brushless, rare earth magnet motor. They could do this for window motors too, and seat, etc though hopefully people don't need to use those enough to matter.
The more I think about it, the more I think the design is not so much about efficiency as it is about uniqueness and handling complex windshield shapes. The majority of friction is the wiper blade against the glass and energizing a magnetic motion-block has to be lossy.
Fox news did a bit of ad-libbing with the statement "Tesla's design mounts the wiper arms to electromagnetic guide rails that can operate more efficiently thanks to reduced friction." That is not accurate. The patent only reads "electromagnetic moving block induces minimal friction", which by itself does not necessarily mean the REST of it is more efficient. That statement is backwards a second way when it states "electromagnetic guide rails", while the patent is for permanent magnet guide rails and the electromagnet is the moving block.
The same thing could be said about conventional wipers relative to the blade-glass friction, and it can't be assumed that the overall design is more efficient than conventional wipers. Suppose it had the same actuator/motor efficiency, then it would be less efficient than conventional designs to sweep over the entirety of the windshield whether dry or pushing water off the larger surface area. Presumably when it is raining there will also be water in that guide rail so that is another impedance reducing efficiency.
If not for the rails clogging or added expense, sweeping the entire windshield seems desirable on an ICE vehicle that has plenty of power to spare, though being just a concept we have no idea how it stands up to common problems like snow or ice on the windshield or in the track.
Ironically even then I think they did it backwards. The wiper arm should have the permanent magnets instead of the rail so it is not dependent on moving wires or a friction electrical coupling (also called "wipers" in the electronics world) to that moving electromagnet "block". Electromagnet rails would also produce some heat to help keep it from icing up.
It seems so backwards to me that I almost wonder if the author of the patent was not the creator and accidentally got the concept backwards. It makes far more sense to have an electromagnet rail aka rail gun configuration.