What is the crowd's opinion of Magnetohydrodynamic Electrical Power Generation (UNESCO Energy Engineering Series)?

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The Rocket labs approach to electric turbo-pumps is not scaleable and not the best way to approach considering the source of electricity being Lithium batteries. One way to change this would be to use the MHD generator driven by combustion chamber exhaust gases of the rocket. The MHD generator has efficiency at about 5% and would be easily scalable.

One of early prototypes described in UNESCO MHD generator was 1 MWt MHD generator driven by rocket engine. At the time I was reading this book it seemed silly, using a rocket engine to produce 1 MWt of electricity at miserable efficiency and now I can see the potential if you take that generator with you on the flight. Imagine things that could be achieved if we have 1 MWt of power generation per Merlin engine on Falcon 9 . This would be almost free energy that has very little overhead to produce and easily scalable. The overhead would be the weight of the generator and associated electronics.

OK I admit that it is not that easy, but would be just Engineering challenge to achieve, and clearly would be the great way to improve the ISP of chemical rockets.

Currently JP Aerospace is experimenting with MHD generators but at very amateur/low funded manner. And they have a video showing experimental MHD built on top of model rocket engine.

Not much work is being done in this respect using rocket engines by any other company. Maybe SpaceX can step up to the challenge and electrify its fleet?