Long story short, I give that episode and their reasoning for electric propulsion an "F" grade on the sincerity scale.
I agree with you on Uma. They went into it kinda ignorant but at least honest cheapskates. I cringed a lot as they made what were obvious to me mistakes though, and then it went sideways when they didn't report honestly what they learned (Which would have dampened the enthusiasm for electric and their whole cooky eco warrior theme they have going on) But that tends to be the way I guess. Their system, originally, for all its flaws, WAS cheap and did work. objective reached! Admirable in that.
I'm not suggesting electric propulsion is bad, in fact I recommend it to clients where it is a viable technology for their use case.
But there are a lot of factors to consider.
If I converted to a turnkey commercially available electric system (with only 8 hours at 5 knot range) ) I would have as much money and weight into it as I would a diesel system with 34 hours at 5 knot range.
What's more, the diesel system can be refueled very inexpensively in about 10 minutes, whereas the electric system will take at least 24 hours, and cost at least one night of marina fees.
On my cruising boat, after motoring 30 hours at 5 knots, I start looking for a marina with diesel as I have about 4 hours left.
If one will be doing a lot of motoring, like down the ICW, or just getting from one anchorage to another between norther's, an electric propulsion system is not a viable option, without an ICE generator onboard, and then what is the point?
I think there are some advantages to this arrangement -- Electric prime mover for the reliable quick anchor set/docking/get out of the way/short hop, and diesel genset for induction cooktop, microwave and air conditioning at anchor, and longer 30-40 hours of motoring @ 5kts. It's the direction I'm going.