Teardrops n Tiny Travel Trailers

I just bought a small Mullins cargo trailer, that has fiberglass body and plywood floor. I'd like to make the floor waterproof. Stumbled upon this product on youtube.
https://www.youtube.com/watch?v=rxdyteoA2Zk
Do you think it would be a good product to coat the bottom of the floor? Or else, what would be your suggestions? Thanks!

That looks awfully thin, can't see it having a whole lot of elasticity and I didn't see any mention of how elastic it is on their page. I'd try to dig up more info. That stuff is about twice the price of most elastomeric roof coatings out there that are much thicker and have been on the market for decades and used by roofers, for instance Henrys roof coatings.

Thank you for the response! Now I'm just considering epoxying the plywood bottom. That seems to be the reliable way of waterproofing.