Liquid Roof! Whats the worst youve seen it fix?

I used a product called Kool Coat on my EPDM roof, and it was still fine 12 years later. Wash first, then prime it, then two coats of Kool Coat. An added bonus was it stopped the black streaking/dandruff problem. I would do the structural repair. If you go over dry rot your repair will not hold up.