versioningState default for createDocument?

Section "2.9.6 Document Creation and Initial Versioning State" describes that repositories MAY create a new Document in a "Non-Major Version" state."

However, the default versioningState for createDocument is to create documents in a "minor" state.

Some repositories can support creation in major or minor, but some repositories (e.g. Documentum) can only efficiently create documents in a major versioningState.

What was the rationale for making the default minor? Do any repositories support minor creation only? It seems that major would be a better default, allowing repositories that do not support minor creation to error with notSupported when minor is explicitly requested.