If you tried to use your marinade as a sauce you'd probably find that, because of the protein it picked up from the meat, your sauce would be cloudy. Personally, I wouldn't try to use the marinate recipe you describe here for a sauce.
Even though a marinade can be used as a basting liquid or sauce, it must be cooked thoroughly to kill destroy bacteria it might have picked up from the raw meat. But, as others have pointed out, I don't believe you'd want to braise or stew a pork tenderloin. There is a French dish that uses its marinade for stewing (Boeuf en Daube) but it uses beef, not pork, and the marinade is boiled for an appropriate length of time to destroy bacteria before it is used to stew the meat.
I've seen some recipes where the marinade was used to baste meats whild BBQing but, here again, the marinade is boiled for an appropriate length of time to kill any of those nasty bugs before it is used as a basting liquid.
Remember too that you have a lot of sugar in this marinade recipe. Sugar burns so, even as a basting liquid, it would only be used during the final stages of cooking to prevent burning.
