The above photo is from a variety called Royal Burgundy. I also grow Purple Teepee, Velour, plus others. Actually I like growing colors other than green simply because they are easier to see for harvesting. The green ones tend to blend in and often get missed. But the purples, yellows, and striped ones are fairly obvious. And besides, they are pretty. Perhaps they are more nutritious because they are colorful, who knows.
I grow beans year around. And I often have an abundance of fresh beans available. We prefer the French filet types, the ones with the thin pods. Picked young, they're really good. But I've found some standard types that are really more flavorful, like Black Valentine. I guess I consistently grow about 30 different varieties. I do that because some will do well under different conditions -- dry, wet, cool, hot. Since island weather can be really variable, I cover all the bases. That way I get to eat snap beans year around.