The idea is very simple and self-explanatory. With this new feature, some models will serve a single purpose: bringing life to the map.
On top of that, I believe it could slightly improve performance, since the CPU won’t need to check collisions for that specific model either.
For example, take this grass added by the map creator:
Now imagine if the creator decided to place a thousand of these across the entire map. The player would have to constantly jump just to move around! This breaks immersion and gradually frustrates the player.
My suggestion to improve this even further is to make the model become transparent when the camera gets close — just like it happens with the player avatar.