add reasoning for using optional dependency

Author: HomelessDinosaur

docs/guides/python/blender-render.mdx

@@ -52,7 +52,7 @@ We can then resolve our dependencies.
 uv sync
 ```
 
-We'll also add [bpy](https://docs.blender.org/api/current/info_overview.html#python-in-blender) as an optional dependency. This is the API that will interact with the Blender environment for setting up and rendering our scenes. The version of `bpy` should match the version of Blender you intend on using.
+We'll also add [bpy](https://docs.blender.org/api/current/info_overview.html#python-in-blender) as an optional dependency. By making it an optional dependency, we can choose to only install it for the containers that require it, reducing the size of the containers. `bpy` is the API that will interact with the Blender environment for setting up and rendering our scenes. The version of `bpy` should match the version of Blender you intend on using.
 
 ```bash
 uv add bpy==4.2.0 --optional ml