[Cpoll]

Alternatively, they speak a different language with different terminology and are translating. I know a few climbing terms in French and they're quite different.

What would be helpful is commenting on whether their assertion is correct or not w.r.t efficiency.

[snowwrestler]

It’s definitely true. The high visibility of holds in the gym makes it easy to move quickly, even your first time up it, which saves a lot of energy.

Outside, the good and bad holds are probably the same color, and may be oriented in weird ways that require some feeling around to find the best way to grip them or stand on them.

Over time, climbers outside can learn to read the rock and make very good guesses about how to reach or step for the next usable hold. But it takes time to learn, and is somewhat location-specific because of the widely varying geology of climbable rock.