Answer

It should be Ruth and Esther.
In the second book of my quartet, the fourth section is devoted to parallel planes of explanation. There I pointed out examples of cases where we accept several reasons/explanations for one phenomenon (Newton’s apple, the sadness of the Happy Prince, repentance or leaving religion). I did note there that in principle this is not possible, because a cause/explanation is supposed to provide a sufficient condition for what is being explained / what is caused. Therefore, either there is a mapping between the explanations (for example, each is at a different resolution, like a biological and a physical explanation for the same phenomenon), or each one on its own is not really an explanation, and only all of them together make up the explanation.
I think the term “benefits” is common in this context, and seemingly its literal meaning is “what comes out of the commandment.” Benefit in our usual sense is one particular case of that. But if you mean everything that results from the commandment, then it seems to me that every reason would be of this type.
At one time I wondered whether every reason is necessarily a fence / safeguard, since to give a reason means to make the commandment depend on something else, and that would seemingly be the safeguard. Admittedly, this is mainly relevant to reasons for prohibitions, but one could similarly suggest reasons for positive commandments as “safeguards” for a positive commandment too, meaning something that promotes doing something else. But there my conclusion was no. There are reasons for a prohibition that are not safeguards (for example, when the bad outcome comes directly from this act itself and not from some other act that it will lead to). And the proof is that although we do not derive law from the reason of the verse, there certainly are reasons in practice (as Maimonides wrote, for example), and nevertheless it is accepted among the later authorities (Acharonim) that there are no safeguards in Torah-level law (the well-known words of Atvon DeOraita bring exceptions to this rule). In any case, if a benefit is a result (direct or indirect), then it seems to me there is no room for anything else. Even viewing the prohibition or commandment as a means of creating commitment to God’s word, without any intrinsic value in that act itself, is still making it dependent on a result.