It may help the doctor make a better diagnosis and in some cases, cure the problem. There are some risks when you have general anesthesia. Discuss these risks with your doctor. A local anesthesia may not numb the area quite enough and you may feel some minor discomfort. Also, in rare cases, you may have an allergic reaction to the drug used in this type of anesthesia.
Local anesthesia is considered safer than general anesthesia.
Your bladder could be punctured. You may not be able to urinate. If you have a lot of discomfort, you may need to have your bladder drained with a catheter temporarily. Infection and bleeding may occur. Precautions, of course, are taken against these risks.