I agree with your accessment. A younger person would have worked better. But it still worked with Klugman. I think they used Klugman cause he was a really good pool player in real life.
Of course, we were just watching a “Twilight Zone” version of “The Hustler”, anyhow. ;-D
I always got a kick out of both, since the character of “Fats” was based on Rudolf Wanderone AKA Minnesota Fats. Before they upgraded it to a 5-star hotel, the Hermitage Hotel here in Nashville is where Minnesota Fats chose to retire. They let him keep his pool table on the mezzanine above the hotel lobby. Every time I’d drop by the hotel as a youngster, I’d pop up to the mezzanine to see if Fats was playing. Alas, he was never there when I visited.
https://en.wikipedia.org/wiki/Rudolf_Wanderone