Most productions have too many audio assets to keep them in full resolution and quality. Most, if not all, of that audio content will have to go through a certain level of compression to fit inside the audio memory budget. It can be argued that the more compressed an audio file is, the more it loses in quality and detail. However, the audio artifacts greatly vary depending on the nature of the sound and their frequency content, and often you can end up with an extremely compact file without anyone noticing the difference.

While you could reduce the quality of an audio file before you import it, the best practice when using Wwise is to import the highest quality and apply Conversion Settings for each file in the project directly. This gives you the advantage of being able to come back as many times as you need to find the perfect balance between having the smallest file size and the best audio quality.