"What's the point?" is the best translation and it's quite a common phrase in French - the literal translation can be taken as "to what to is that useful?" It means kind of like "what would be the use of that?", and by continuation "for what reason?" or sometimes just "why?".

right ^_^ , you could use this sentence for ask about the usefull of an object or about an action --> if someone made (or wants to make )something and you don't know why, you don't understand the usefull... just say this ^_^ In some situations, when people ask me if I want to make something and if I don't want because i think it's useless, I say this. In this case even if it's a question, people don't need to answer if they're agree with me. And if they're not agree they'll say me why :) Do you understand my english >_<'

It is a rhetoric question and means as well: "What is it good for?" Here the speaker knows the answer and thinks that subject matter is good for nothing or serves no aim ,but still asks and use this kind of question to confirm his view.