Why do minor versions (drafts) on SharePoint 2010's Page's library enable the Publish tab? I've noticed that when you turn minor versions off on the publishing Page's library, the Publish tab goes away. I've never understood the significance of that. Thanks.
The Publish button becomes pointless if minor versions are disabled as Check-In automatically creates the next major version. With Minor versions enabled Check-In merely creates the next minor version and 'Publish' is required to promote the document to the next major version.
In smaller environments where one person always makes changes to a set of pages then the Minor versions are not really needed. However, in larger environments it is common for multiple people to work on a document between major versions. The only way to do this is to enable minor versions which then allows all the people working on the document to check it in and out without publishing a new version.