Embedded alpha vs Luma Matte

I've uploaded quite a number of clips with embedded alpha channels for easy compositing (encoded in PNG format). But for some reason, if I upload a version with a Luma Matte or with a green background for keying, those sell better...

Anyone else seeing similar results?

Any buyers wanna jump in here? Do you need help understanding built-in Alpha vs Luma or Keying?

Yes, I see the same. I am almost wondering if it is worth keying at this point. From many discussions have had with people in the biz, many really don't understand the concept or what even an alpha channel is.Go figure - we try to save the buyer's time and it really doesn't as they usually don't understand what it means. Perhaps they are used to seeing a segment with the actual matte as well? Or we need to label things "multimedia" - bogus for sure.