Yes, uniforms are highly advised in countries that have a predilection for bling, braid and badges as well as a penchant for triplicates of useless paperwork. It's not about a power trip, it's about making things simpler. Pilots there are expected to be in uniform, either military or civilian. For a pilot not to be in uniform often just arouses questions that are just not worth the hassle on a long day.
I know of one company that frequently positions empty and the decision to wear uniform is usually based on the aforementioned matters!