The advantage is that you can work with the appropriate tools on the relevant areas of the layer mask to create a perfect layer mask. Here's what I mean....
I'm using this image (cropped) that's in the public domain under the CC0 license: You can download it from here:
https://www.pexels.com/photo/woman-brid ... ait-24806/
The woman's head and hair demands the use of a soft-edged brush to paint the soft edges of the mask; but the rest of her torso has an edge that is distinct and lends itself perfectly to using the Vector Lasso tool.
So, these are the steps I used on this image:
- I used the Quick Selection tool to define just the area around her head and hair.
- Then I used the Border Matting tool to refine the selection and separate the head and hair (against a transparent background) onto its own layer.
- Use Tool...Mask...Create from Alpha to create a raster image mask of the head and hair.
- In the Layers panel, drag that image mask onto the background image as a child layer.
- Delete the no-longer needed head and hair layer. It's served its purpose well....
- With the background image as the active layer, use the Vector Lasso tool to create the vector lasso for the torso, making sure there's an overlap with the head area.
- Click on the "Convert to Clipping Layer" icon in the settings panel for the Vector Lasso tool to create a clipping layer.
- Drag that clipping layer to become a child layer of the original background layer.
- Select both the vector clipping layer and the image mask and group the marked layers. This should automatically create a layer mask group consisting of the image layer and the vector layer. If things don't work, make sure that the layer properties of the image layer and the vector layer are only "Show", and the layer properties of their parent group are "Clip" and "Layer Mask". It's important that the order of the layers is as shown.
Because the mask for the torso area is a vector clipping layer, it's very quick and easy to refine the masking along the long curves of her arms and the intricate details of her dress by using the Edit Vector Points tool to move points of the clipping layer.
The important thing is that you can use the most appropriate tool to modify specific areas of the layer mask.
Hope this proves useful!