They don't need FDA approval to market it as an ad

They don't need FDA approval to market it as an additive to paints and stuff (just look at all the toxic crap in so many products like that), but as you say, if it were FDA approved it would help with convincing companies to try it, and also in marketing.

As far as a coating for metals -- they already have the technology to put silver on railings, etc., which absolutely kills viruses and bacteria on contact. One of the cruise lines said they were going to put it on their ships to stop the spread of epidemics on cruises -- then I never heard anything about it again.

I think if you coated railings with it, you'd be constantly having to re-apply as it got worn off by friction with hands. But, I could be wrong.

I think using it in paints etc.as a preservative, and as a disinfectant in the operating room and hospital in general, would be the most obvious application.