The gemara in kiddushin 6a says that if a woman would give a gift to someone who is an important person and doesn't accepts presents from just anybody, she would be receiving enough hana'ah from the fact that he receives her gift so that he can be mekadesh her with that benefit that she receives. The Taz (y.d. 160:8) explains that the reason that he must be an adam chashuv is because if he is just a regular person then the benefit she receives doesn't have any cash value to it and therefore cannot create a kiddushin. The Taz continues to apply this concept to the issur ribbis as well. If a lender tells a borrower, "i will lend you the money you need on condition that you receive this gift from me" - it depends. If the borrower is an adam chashuv then the lender would be receiving real benefit from the borrower willing to receive his gift which would create a ribbis problem. But if the borrower is not an adam chashuv there wouldn't be any ribbis problem. The Taz clearly understands that if the receiver of the gift is not an adam chashuv, we consider the value of the hana'ah that the giver has to be worth zero, and therefore it is not a ribbis problem.
However, R' Akiva Eiger (y.d. 160 on taz) cites a Ran in kiddushin who asks based on levi in our gemara who holds that chalifin is done with the keilim of the makneh, because the benefit that the makneh receives by the koneh willing to accept his gift, provides enough benefit to the makneh with which to be makneh the item. Clearly, we see that the makneh receives benfit by the koneh receiving his gift even if the koneh is not an adam chashuv. This seems to contradict the gemara in kiddushin? The Ran answers that even if the receiver of the gift isn't an adam chashuv, the giver has hana'ah that the receiver was willing to accept, but the hana'ah isn't valued at a pruta. Therefore, in the context of kiddushin where her hana'ah must equal a peruta, it only works when he is an adam chashuv. But, by chalifin where the benefit received by the makneh need not be worth a peruta, even if the koneh is not an adam chashuv it will work. R' akiva eiger explains that the rav doesn't disagree with levi about this. Therefore, in the context of ribbis where even a slight benefit that the lender receives from the borrower is an issur (although not d'oraysa), even if the borrower isn't an adam chashuv, there would be a problem of ribbis. Based on this, the lender cannot say to the borrower "i will lend you money on the condition that you receive this gift from me", even if the borrower isn't an adam chashuv because the lender will be receiving some minor benefit which is assur.