In general(not counting where you live), Spotteds are more rare than Painteds. In fact, MUCH more rare. Also, Spotted turtles are extremely beloved by many who have kept them. They are very intelligent and even sweet turtles. I'm not bashing Painteds, but Spotted turtles are in a totally different league.

Legal protection is another reason. Nothing raises the price of an animal like saying, "You can't have one".

I'm assuming you are a snake person. Think of it as the difference between a Black Rat snake and an Eastern Indigo. In some areas of GA, Eastern Indigos are nearly as abundant as Black Rats. Well, maybe not any longer, but they used to be not that long ago.