Photoshop allows users to create a contiguous mask, so why can't any of the color key effects in Premiere Pro?

This is one of those requests that are so obvious, it doesn't really need an explanation regarding why it would be beneficial. After all, the benefits of contiguous selections in Photoshop is clear as a bell. ;)

Please add this option to all or, at the very least, one of the color key effects in Premiere Pro.

Thank you! :)