Personally, I think reading is reading no matter how it's done. That said, I think that audio and Braille serve different purposes, but even then, the lines between how beneficial those different purposes are for each individual can get blurred pretty quickly.

Let me try to elaborate on this a bit, because I find this to be a fascinating question.

If one is blind from birth, or otherwise unable to read print by the time they should start reading, I am a firm believer that they should be taught Braille. It's essential that spelling, sentence structure, and so on is conveyed to you in a format that is tactile, and is as close to what the sighted get to print as possible. There are certain things that you just can't learn by using audio alone. And, if that's all you've ever known, things can get messy pretty quickly.

The other side of this is that when we watch a movie, technically we're only listening to it, whether it's described or not. Yet most of us find it insulting when sighted people try to tell us that we listened to said movie or TV show. So of course, even if you listen to an audio book, I feel like you're still reading it, because even a sighted person might listen to a book on their way to work, or when their hands/eyes are otherwise occupied. I bet they wouldn't like it if they were told they were listening to their book, though.

So it all falls under the same umbrella of terminology, and whatever works best for someone at any given point in time is still their way of reading.