Welcome to Photoshop Gurus forum. Register a free account today to become a member! It's completely free. Once signed in, you'll enjoy an ad-free experience and be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
So it's just a blend mode
They already have a blending mode section and this does the same thing
I agree with Tom. I was like you Dave, when I first became aware of the feature in a Corey Barker tutorial, I thought it was nuts! I did not understand it no matter what how I reasoned with it. Now I use the feature all the time especially for alpha channel selections. I like the ability to blend two different alpha channels to achieve the best contrast between white and black.............there's no other faster or convenient way to accomplish that.. Like Tom said, it's an acquired taste.