Whether or not the device works - this usage of minute is also apparently unit of radio power or backlight luminosity, if cell phone makers and reviewers are to be believed. Declaring crack-pot status based on that usage is kind of over-the-top, unless you're here to argue that cellphones don't exist and are mere crack-pot theories as well.

If you take careful note of my wording, I said that every crackpot makes this sort of claim, not that only crackpots make this sort of claim.

The reason I know this is crackpottery is that, as others have pointed out, the physics just doesn't add up. Assuming perfect efficiency, you'd be looking at somewhere on the order of 1% of the light output from a standard 40 watt light bulb.

See the numbers below. It's about the equivalent of a 2 W incandescent bulb, or 5% of a 40 W bulb; but more importantly, it's comparable to a kerosene lamp, which is what it's supposed to replace. So I don't think a "crackpot" charge is warranted.

It is warranted because the physics doesn't work out

Um, did you look at the numbers? The physics does work out, at least to a rough order of magnitude. That may not be enough to make it a practical success, but it's enough to make "crackpot" unwarranted.