Which would be better for you?

Following on from previous questions, another point:
 
If I accept the argument that “something” was given at Sinai, I can argue that it is also very likely to be extended. It is hard to imagine that an entire group would take on such an oppressive and arbitrary religious obligation, with such a level of piety and fanaticism, without convincing reasoning. So, while it is not entirely clear what the content of the commandments we received at Sinai was, whether they were well kept, and whether “noise” was added to them, there is nevertheless good reason to think that the *reasoning* for why the commandments should be kept was as smooth as the historical account itself. If I promised the children a lemon popsicle, it is unlikely that I would be able to convince them – all of them at once – that I had actually promised them raspberry juice.
It follows from this that there is considerable credibility in the biblical text and tradition regarding the question “why one must keep the commandments,” even if there is less credibility in the question of which ones.
At the end of “The First Commandment” you dismiss the “because it is beneficial” argument as a valid argument for why there should be a religious obligation. But almost everywhere I see in the biblical text, when we are challenged on this issue, this is the answer. Because it is beneficial. It is good. For us and for our children. It prolongs our lives here in the land and makes them good.
 
 
Maybe this is a valid argument? If I believe that the Torah was given at Sinai, and that this Torah included commandments and instructions, and that the reason for keeping them was also given and is – so that it will be good for us, then maybe this is a good enough reason and no others are needed?
Whoever/whatever was discovered at Sinai probably has miraculous powers, so it makes sense that he knows what is good for us. It is very reasonable to trust him. Even if I find it burdensome, he knows better than me. Therefore, I should listen to him and keep his laws.
Does that make sense to you?
 
Another thing that may stem from this is that if there are commandments that – clearly! – do not do us any good, then they are probably ingrained errors and perhaps we need to look for ways to eradicate them. Because by definition they cannot be commandments. Of course, it is very difficult to prove that a commandment necessarily does harm. It is possible that genocide will do us good, in unknown ways that are difficult to explain and wonderful beyond human understanding. But still, theoretically, the commandments are supposed to do us good, and this provides a conceptual opening for attempting to set criteria and tests for the question of what is a true mitzvah and what is an ingrained error.
What do you think about things?