Sigma 30mm - Keep it or not

I bought a Sigma 30mm a week ago. I have a Nex C3, 18-55, 16mm and ultra wide angle adapter. There was no real reason to buy the Sigma other than its reputation as a sharp lens. Although, I took some good portraits, I find it not wide enough for landscapes. Do I really need a 30mm when I have 16mm and 18-55 kit? I can return the 30mm before end of next week. For almost the same money, I can buy a new C3 body from Ebay, so I can have one body with 16mm and another body with 18-55. Is this a crazy idea?