I've heard of and read about that process for asphalt shingles. It basically makes them almost "like new" again. You've not put on a new roof per-se. Just extended the life of the existing roof. That would be a maintenance expense, even if it included replacing some of the fascia boards if there were a few rotten ones that needed to go.
If not to much trouble, if you have a 4-point inspection done anytime after this treatment, I'd be interested to know how much life the inspector estimated the roof has left, as well as when that roof was originally put on.
