I’ve seen the tv spots touting its uses, but have not tried it. The rubberized aspect of the product makes me wonder about its suitability for scenery purposes (although if you can make a boat out of it, there must be some rigidity once cured). I have used a couple of the other products for sealant purposes, and those have performed admirably.
I wonder about the cost, and whether or not it would take latex paint. I know from experience that very good ventilation is needed when using (a great product, by the way) FlexSeal spray - not sure about the paste.
My suggestion is to stick with tried and true products for scenery