I think it could depend. Back in the 80s I gambled with Ray Martin even in one pocket. I knew who he was but thought he was an old man and couldn't play anymore. Turns out he wasn't that old and could still play just fine. I lost every rack but we had good battles and long games. He played very, very conservative. In that session, I did learn a lot. A real lot.
Another time I gambled with a teenage Dennis Hatch even in one pocket. I knew who he was but thought he was too young and inexperienced to be a good one pocket player. Turns out he wasn't that inexperienced and played great one pocket. I lost every rack but the difference was he was very aggressive, hardly ever missed, and every tiny opening I gave him cost me 6, 7 or 8 balls. No games were close. In that session, I didn't learn anything.
I'm guessing if that old Ray Martin would match up against that young Dennis Hatch, it would be a battle, and Ray might even have the better of it. In this case, I learned more from the better player because of his style and strategy choice to out move me instead of out shooting me.
On a side note, Ray never used the same break twice. I only knew one break and had no idea there are several. Going by memory, splitting the first two balls is the most aggressive. All the other breaks spread the balls less with less risk. Those breaks drug out every game into defensive / maneuvering battles. I lost a lot that day...should have pulled up much sooner.