Mr. Laser Beam wrote:
^ It's not meaningless. As I said, separate rank systems exist for a reason.
But what is the reason, aside from evolving separately over a long period? There is no essential requirement for a certain set of titles over another. The US Navy's Seabees are organized into a Naval Construction Division commanded by a rear admiral, regiments commanded by captains ("commodores"), battalions commanded by commanders and companies commanded by lieutenants. Everyone understands and it has worked well for 70 years.