Should benefit be followed by 'of' or 'to?'

Here is an important benefit to speaking English as a native language. Based on the context, it's easy to decide which preposition follows which verb, noun or adjective.

For second language speakers, these decisions can be a little harder to make. Fortunately, it's easy for a native speaker teacher to tell a student which preposition is correct in a given context. What's often a lot harder is explaining the reason for a certain choice.

Recently I was asked about the following sentence. There are many benefits of using cash. "To", I said. "I'd prefer you to say that there are many benefits to using cash." But why? I wasn't sure.

Here's another sentence. The main benefit of using cash is convenience. Here I definitely prefer of. Again, I asked myself why. Why use different prepositions in these two sentences? The meaning of benefit is the same in both cases.

I checked the Oxford Advanced English Learner's Dictionary and found these examples: to have the benefit of a good education, and to reap (or enjoy) the benefits of one's hard work. The same source also provides this example: "The insurance plan will provide substantial benefits to your family..." (OUP 8th Ed).

Finally, I consulted a linguist, who investigated a couple of possible reasons and then explained the answer. When the phrase containing the word benefit appears in the subject of the sentence, benefit is followed by of. When the phrase containing the word benefit appears in the predicate of the sentence, benefit is followed by to.

She used the following sentences to indicate what she meant:

There are five benefits to skiing. (correct)
*There are five benefits of skiing. (incorrect)
The benefit of skiing is getting out in the fresh air. (correct)
*The benefit to skiing is getting out in the fresh air. (incorrect)

These sentences check off perfectly with the ones above, and I am satisfied that this is the correct explanation.

Linguistic note:
The benefit phrase always subcategorizes for a noun (especially a gerund).Any other linguist or native speaker out there want to weigh in on this? If so, please leave a comment.