Or perhaps the prohibition on replacement produce in the mishna is due to the fact that replacements of the produce are viewed as being like that which grows from them? They are both forbidden because they derive from the forbidden produce. If this is the case, it is no different for him and it is no different for another. Neither may derive benefit from the replacements.

Rav Aḥa bar Minyumi said: Come and hear a proof from a baraita: With regard to one who says to his wife: Benefiting from me is konam for you, she may nevertheless borrow money to sustain herself, and the creditors can come and collect her debts from her husband. What is the reason that the creditors can collect from the husband? Is it not because she benefits only indirectly, and it must be that replacements, i.e., the creditors’ money, are not like that which grows from the original item?

Rava said: This is not proof: Perhaps it is the case that one should not benefit from replacements ab initio, but if one did it, it is done after the fact. Since the wife lacks any other means to support herself, the case is considered to be after the fact, and it is permitted for her to benefit indirectly. Still, replacements of an item are considered to be like that which grows from it ab initio.

Rather, come and hear a proof from another mishna (Kiddushin 56b): With regard to one who betroths a woman with fruit of orla, i.e., fruit of the first three years of a tree’s growth, from which it is forbidden to benefit, she is not betrothed because the fruits have no value. Betrothal can be performed only with an object worth at least one peruta. But if he sold them and betrothed her with the money he received, she is betrothed. Evidently, replacements of a forbidden item are permitted. The Gemara responds: Here also, one should not benefit from the replacement items given in exchange for the orla ab initio, but if one did it, it is done after the fact. Replacements of an item may still be considered to be like that which grows from it ab initio.

MISHNA: If someone says to another: I am hereby forbidden to you like an item dedicated to the Temple, then the one prohibited by the vow is prohibited from benefiting from the possessions of the one who took the vow. If someone says: You are hereby forbidden to me like an item dedicated to the Temple, then the one who took the vow is prohibited from benefiting from the possessions of the other. If he says: I am hereby forbidden to you and you are hereby forbidden to me like an item dedicated to the Temple, both are prohibited from benefiting from the possessions of the other. But it is permitted for both of them to benefit from the objects belonging to those who ascended from Babylonia, i.e., common property of the nation as a whole, which is not considered to be the property of any individual.