Though there are audio sites out there on the web that will host audio. Sometimes you may not want the recording to be public out on the web. In that case hosting audio on the VLE may be an ideal solution.
If the audio is of a lecture on a tricky subject, or contains licensed content that you can place on the VLE, but are not allowed to freely distribute then placing the audio on the VLE may be a better option than uploading to a public site such as Audioboo. Sensitive recordings of research subjects, or patients, are more reasons why you may host the audio on the VLE.
The final key reason you may want to place the audio on the VLE is that the recordings are of or by learners and they may not wish to have their work or their views available publicly. Of course there are sites out there that can be password protected, but at least the VLE does most of that hard work for you.
Audio can be useful to enhance and enrich learning, one lecturer I know records short summaries of the lessons and the assignments. Some learners find this more engaging than reading them on paper or on the screen.
Recording debates and discussions, allows learners to reflect and review them at a time and place to suit the learner, rather than just relying on notes and memory.
By placing the audio on the VLE, you can place it in the context of learning, enabling learners to clarify how the recording works in respect of the rest of the course or topic.
For ease of access, by placing the audio on the VLE, the learners will be able to click and download the audio file to place it on say a mobile device.
Though the server may not be configured to deliver or stream video, it is often much easier (and places less technical demands on the server) for the server to stream audio. From a learner perspective, audio requires less bandwidth than video, so can often be easily accessed on poor internet connections such as mobile internet.
Teaching has had an oral tradition that goes back for thousands of years. With a virtual learning environment, using audio recordings can allow learners a choice on how they access content, instructions and advice.