To get into the technical details, that's a very complex question. For one thing, even if valid, are the features language-specific or cross-linguistically valid? Can we say that English and Hindi have the same voicing feature but only Hindi uses the aspiration feature? (Abstracting from what they might be called specifically in a given theory.)
The point is that the phonemes contrast in one language in a way they don't in another.
From the perspective of a student, operating under the understanding that the features and phonemes are essentially the same thing and that you can reasonably compare languages this way is both useful and relevant to what you'll read about. From a deeper theoretical perspective there are various things to work out that are still uncertain. What "is a feature"? Is it a gesture? A mental construct? A cross-linguistic property of Universal Grammar? Is it even a thing, more than just a convenient notation system?
It's hard to answer these questions in the abstract. (Also, as I've probably mentioned to you, phonology is not my area, so for a state-of-the-art answer on some of this you should check with a phonologist. I believe what I'm saying is in essence reasonable, and I know the situation is very complex, but check on any details you need to know more about.)
Also, importantly, the answers to these questions depend very much on your theory (and which particular version of it your textbook uses). So while nothing is certain, if your textbook says something, that might be on the exam
