As you said, cash playing is more focused on mathematics, whereas tournament play has more psychology involved. I don't know that either is better than the other, though it is perhaps easier for a cash player to learn the psychology of a tournament than for a tournament player to learn the mathematics/adjust to not being able to rely on the psychology.
That said, there is a computer that can beat a human player at a cash table. I don't know that there is one that can win a tournament.