BCC Pixel Chooser Standalone

I really feel like I’m beginning to get the Pixel Chooser built into a lot of the BCC filters but it also exists (as the documentation likes to point out) in a standalone form. Excellent so I can apply this and it will show me the tracked pixels that have been selected. But what I’m not clear on is how I can use this!

Clearly for the BCC controls with this built in I can use it to limit the filter to those chosen pixels and I assumed that this would allow me to apply the same technology to filters that aren’t in the BCC collection with this built in. The only way I have seen to use this (in Vegas Pro) is to apply the effect to footage and then add another effect in the chain after this (e.g., VEGAS HSL Adjust) tweak the parameters then drop another copy of the original footage on a lower track and make sure the Pixel Chooser is set to Output Alpha Channel. This then displays the footage underneath as normal and the cut out section with the amended HSL settings. Is there another/better way to do this or am I essentially doing it the way it is intended?