I'm not sure, but I think the WA-specific skills level faster, period. My sim went to China and maxed out Martial Arts within one 5-day trip, without the "Disciplined" trait, the "Genius" trait, the "Athletic" trait, OR the "Fast Learner" reward. Compare that to his Music and Charisma skills, which took him forever to max out, even with the "Charismatic" and "Virtuoso" traits. Photography seems to level super-fast too.
None of my non-French Sims have learned the nectar skill at an accelerated rate. I haven't had any Sims learn photography, but I did have one max Martial Arts. He didn't seem learn it any faster than a regular skill, and he was using a training dummy at the library with the Disciplined trait. I never sent him to China, though. I wonder how or if that makes a difference.