Quibble over the names if you like. But before a cell can use a fat, it has to be broken down to single units in length. Vinegar is already, so probably is rapidly absorbed. Just as single-unit sugars are. So it may have some effect on metabolism.
It is well known that fatigue can be caused by a shortage of fuel in the body. Not sugar, I can check for that with my glucose meter. Apparently triglycerides. I have personally had my fatigue dissolve after eating a pad of butter, with it's short chain buteric acid. But that is anecdotal. Vinegar has a short unit already. But even at 1% is pretty harsh. Butter and beef fat are both about 4% buteric acid. Coconut oil is high in medium chains. Any supplemental source of di- or tri- whatevers for me to try next time?