Only watched parts of the video - he waffles on too much to hold my attention - but interesting stuff, what I did see.
I don't think I'd want to use the stuff for a NMF, when there are now so many good products around, compared to even a few years ago. That AK Interactive metallic range is one I want to try soon.
I've been using a similar chrome pen for years, the current one having been in use for some 5 or 6 years, and bought at the local office supply store, and I use it for oleos, cable clamps, lamp reflectors and similar small fittings.
It's made by Mitsubishi Pencil Co., and called Uni Paint Marker, and described on the pen barrel as 'Oil based, Opaque', 'mark on any surface'.
They have a range of metallic colours, as well as 'solid' colours and a few fluorescents.
Some of the 'solid' colours can be useful for such things as window seals, or for fine lines where a brush and / or masking would be difficult to use.