Yes, that's right in my experience. Less than 20º for consumer German blades and the steel rolls too far, dulling the knife more quickly. I usually go for the slightly higher 22º range for the same reason, and polish an extra bevel for smooth cutting. But then, a lot of the knives I see don't get any maintenance except steeling for a year or more, at which time they come back to me.

The additional 2-ishº isn't really necessary for new knives, but knives get "fatter" as they wear over time, and this technique thins them a little, restoring them quite well.

And I agree that the harder steel in the thin Japanese blades is more vulnerable to chipping and cracking with heavy-handed use. That's the trade-off, at least with the stainless steel blades I've come across. I can't speak about the Damascus-style carbon blades.