Why does Annie use a revolver as her primary sidearm when everyone else seems to use semi-automatics?

In the TV show Covert Affairs the lead character Annie uses a Chiappa Rhino revolver as her personal/primary sidearm. This seems to be a distinct stylistic choice for Annie because everyone else seems to prefer semi-automatics. Furthermore the Rhino has a very distinctive design which is different than most revolvers.

Why did they choose to give Annie that pistol, and what is that supposed to say about her? I don't think most of the main marketing points for the Rhino's design are a particularly relevant given that:

• Annie is seen as proficient with semi-automatic pistols multiple times in the series while under duress
• Semi-automatics offer a flatter profile and are easier to conceal.