War Sloop Downgrade from frigate?

[Swordblade]

I'm saving up for a war ship and I'm still deciding which one to get. I went to the game's website and read the chart of all the ships features (Broadsides, Cargo, etc.) and I noticed that the war sloop seemed to have either the same or worse in everything. It held less crew, had less hull and sail points, had the same cargo, had less on deck cannons, and had the same amount of broadsides as the medium sized frigate; and it costs more than 2x a frigate!

Is it just a big downgrade or am I missing something?