Without knowing the condition, it's difficult to say, but potentially they might be trying to intervene with surgery at the optimum time.
They could, for instance, remove Faithdaddy's missus's (Faithsmummy??) gall bladder now, and be done with it. Or they could wait until she's in agony, and there are other complications, which will cause more distress and pain for her, and potentially cost a lot more. Keeping an eye on something that can develop in more than one way or at more than one pace is possibly the most cost effective solution.
But I understand your frustration - especially having an endoscopy you feel is not warranted. It's quite invasive and uncomfortable, which is not something to be taken lightly.