Brianna Wu, writing for iMore:

Metal for OS X is huge — and it’s going to be a much bigger deal on the Mac than it is on your iPhone or iPad. If you use a Mac to produce professional content, chances are, Metal is about to drastically speed up the professional apps you use like Adobe Illustrator and Autodesk Maya.

As long as professional apps adopt it, game developers, designers, video editor, and photographers are going to love Metal.