No argument that our levels of efficiency are limited,
I fully understand that energy cannot be created or destroyed,
but the constraints of today you mention are the conquered challenges of the future.
I'm not being optimistic. Just look at the development of weapons, computers and power generation.
That's a popular ruse of zero point energy proponents. Distracting the audience with 'look how far we've come, what was once thought impossible is now an every day experience' while selling a technology they have failed to demonstrate. Throw in some jargon about tachyon and spinning magnetic fields and the scene is complete.
To reiterate, I agree there is no such thing as "Free Energy" but heck, let the dreamers dream.
Knowledge for the sake of knowledge, this is a true gentleman's pursuit.
Where's the harm besides lost leisure time, so long as they are not scamming?
I have to admit, I did not view the OP's link, figuring is was nonsense.
The problem is the dreamers dream and the suckers spend money buying plans after seeing a fake demonstration on YouTube. People are free to spend their time and money as they please, but pursuing a technology that has been shown countless times and over centuries to be based on self delusion and fraud is a total waste of time.