I think a downloadable file is better. You can upload it in your Sta.sh and link to it in your artist's description. I listened to a story by ^neurotype that way. I reckon I wouldn't usually listen to stories, but that's just because I don't listen to ebooks.
I think audio versions can add something to both poetry and prose. I've actually been trying to set up something similar with my own work, but got a bit distracted. If you're planning to use YouTube, I'd recommend putting something in the video itself, though: while there are benefits to using such a large site, I always find that "videos" with no visual element to them seem a bit cheap somehow. You might also consider something like Soundcloud: that would be good for people like =vglory who want to download a sound file.
With regard to =futilitarian's point about reading prose, I feel like I should mention that while it's not essential, good prose often has (or should have) a particular "sound" and rhythm to it. Consider how things sound when read by a text-to-speech program: there's something off about it, and not just when words are mispronounced. There's more to prose than just sticking words in the right order. Not much more, but more nonetheless.