Useful to make some graphics features like outline/portal/ Dissolve/Fade/X-Ray/etc
We do have Stencil buffer usage for object layer masking (eg. use by Decals) and it can be accessed in PostFX materials for custom outlines (eg. only around enemies). I’ll add task to future roadmap to expose it a bit more to users as we use 5 bits for 32 layers so 3 bits are left unused future future or for game.