[Serious] Generally speaking, is philosophy a worthwhile subject of study?

[Belacqua]

That depends on how you define "knowledge." 

It's wonderful as a source for certain kinds of knowledge.

Mostly the self-knowledge that we don't have many answers.
From what I have seen, philosophy is very good at asking interesting questions that make us pause. That is a good thing.
But it is very bad at actually answering those questions.
And it is worst when it clings to old answers and claims they are the only possible answers.

You've shifted the topic now, from "knowledge" to "answers." These are not necessarily the same.

I can understand that in your value system and ideology, "knowledge" would equal an answer you find satisfactorily persuasive. But that isn't necessarily what philosophy is attempting to provide. 

Philosophy doesn't run by the same rules as your preferred subjects.