Urethane is very condition specific but I don't think you can generalize on who can or cant benefit from it.
A generalization is what most people find to be true most of the time. So I'll reiterate -- in general, in most situations that bowlers see, Urethane is not going to be the best option for low to medium rev bowlers.
I have no doubt your success in the senior high roller sweeper. In the high roller environment, my Hammer Black Urethane would be in my bag for that "just in case" situation. There is too much on the line to assume anything. Along the same lines, I finished a sport shot tournament with a 300-300 using a Motiv Ascent to win $2,000. One of my few moments in the sun. The irony is that I only found one situation in the next 2 years where the ball was the best choice. I gave it away to a Junior bowler last year.
The question isn't if there are unique situations where anyone could find value in Urethane, but how often they occur. For most bowlers, it's almost never. Right now I'm bowling 3 leagues in 3 different houses. One fresh THS, one second shift THS that is wet/dry misery, and a sport shot challenge league. Urethane is MIA as a first ball choice (for all bowlers) in all three leagues. I believe this is far more usual than unusual.