You can legitimately use either 'for' or 'to' depending on the situation, but 'in' seems universally incorrect. "For" has a slight implication of intent or purpose. Contrast these two examples:
... the Jury found, that the captain was perfectly warranted in the sale, and that he had acted for the benefit of all concerned.
My point, Senator Bankhead, is that the compression acted to the benefit of the warehouse, not to the benefit of the cotton shipper that purchased it.
In the first, the captain was doing what he thought was best for "all concerned", so he was acting for their benefit. In the second, it's just saying that the compression happened to benefit the warehouse. There may or may not have been intent.
Consider the NGram: