'To' or 'For'? Usage of prepositions

Question

This is a sentence from Dickens's 'A Tale of Two Cities'. It's from Chapter 11 of Book II. Mr. Stryver accused Sydney of not being agreeable in a women's society and he told Sydney that he felt ashamed of Sydney when they were both with Lucie. Then Sydney rejoined:"It should be beneficial to a man in your practice at the bar to be ashamed of anything."

This ironic sentence should mean:'It's good for a lawyer like Mr.Stryver to actually feel ashamed about something.'

But then why did Dickens use the preposition 'to' here? Should he have used 'for'?

As an ESL speaker, I usually think that 'it is beneficial to somebody to do something' means that 'Doing something does somebody good.'

Is it still a valid prepositional use in modern English?

Answer 1

The Free Dictionary points towards 'beneficial to' where it is defined:

beneficial

1. (sometimes followed by to) causing a good result; advantageous

Cambridge Dictionary has given all example sentences with 'to'.

A stay in the country will be beneficial to his health.

Breast-feeding is extremely beneficial to the health of newborn babies.

From our point of view, we do not see how these changes will be beneficial to the company.

The following examples are from Merriam-Webster:

He hopes the new drug will prove beneficial to many people.

They have a relationship that is beneficial to both of them.

Though not as a hard and fast rule, WordReference.com says the following about choosing 'to' or 'for':

The tricky part is that both "to" and "for" also can serve as prepositions. "For" as a preposition answers "for what", while "to" answers "to whom," so if you have an object of a preposition like Jane or something like that, you'll probably use "to".

Answer 2

In my opinion, the use of 'to' accentuates the word 'should', making it sound colder and more authoritative.

It should be beneficial to...

sounds like a judge, whereas;

It should be beneficial for...

sounds like advice.

This literary device has the effect of doubling the humour - Mr. Stryver thinks he is in for an ear-bashing, in fact he is complimented.