Erase blend mode and custom formula/expression based blending.

I love  erase blend mode  in Affinity photo. You can do clipping be groups  in Photoshop  but erase mode is so  much easier in many cases and can replace a whole  stack  of clipping groups sometimes.

Would also be nice to have  special custom blend modes with access to other layers pixel information .   So instead of doing  complicated groups  of stacked layers  clipping something,  something we sometimes  could't figure out a thing about  just next day, we could just  make an expression :  (Layer1 max layer2) -layer1   for a mask .   Or maybe a displace layer which  using  R and G for vector and B for distance  from an image bellow working on the fly  by an expression . 

  It could simplify  layer stacks tremendously  and be something having usual advantages of layers and still a bit of flexibility of nodes . 

  Start with erase mode  for layers and groups  at least . it alredy able to  simplify the stack in half .