I've learned that when using "for", when meaning "benefit from", you would use "для + gen". But I've also just learned "на благо", meaning the same thing. Are they synonyms? How are they different?
for the benefit of as
для/ради блага/пользы is more accurate than the simple
That said, context is important, and so due to stylistic differences between the languages there could be cases where
для would fit better.
As far as the difference in meaning is concerned, it's much the same as the difference between that of their English counterparts.
Для has a purely utilitarian purpose and meaning, denoting satisfaction of some type of need or requirement.
для/ради блага/пользы specifically stress the benefit expected from such satisfaction. And they sound rather solemn and exalted so to speak.
The two mentioned phrases differ in the way they interact with their indirect object in a sentence. If you're interested in details, please put a note in the comments and i'll expand the answer.