Cool method, creating a new geometry from the bounding box mesh, and projecting the points back to the emitter surface, i did something similar for a pixel based distribution algo few months ago, and another one based on curve-areas ect…
The big problem is that we lose all attributes of the emitter mesh with this kind of data flow 
when we rely on external objects or primitives to create an effect on a mesh, or in this case a new distribution algorithm, all attributes of the users will be lost.
You might say “just use an attribute transfer node” except it cannot work on an un-defined amount of attributes, especially coming from an user perspective who won’t dig into your node tree (either by lack of knowledges or being restricted in the studio pipeline).
It’s one of the biggest limitation i found with geometry node since the very beginning, 
it was brought up in the blender chat last week, I hope this limitation wall will be resolved someday
https://blender.chat/channel/geometry-nodes/thread/mvc3XeG43rvfXxNNa?jump=MbWJNTH8hNu7ssFDh
https://blender.chat/channel/everything-nodes?msg=J4Dh3aM9q7cSNXL9z