The album preview link is a little mislabelled as it's meant for basic info about the release. Discogs is used a lot as well and they only link to videos on some releases.
As the preview link gives info about the specific release, I don't think youtube can be used instead of Amazon, discogs etc.
The uploaders can probably add youtube links as well, but i think it might get too confusing if more mandatory links becomes a demand.
A lot of music releases can't be found on youtube anyway. Some are deleted because of complaints from the copyright owners and / or if an account is closed