I am wondering why this is done and when it is done, surely it then “breaks” your models if you are modelling to scale
Why ? The dimensions of the object will not be affected.
(in LW the object IS the geometry).
The object (object mode) and the mesh (edit mode) are two different things in blender. An object is just a container that may include mesh data, armature data, modifier data, material data, texture data, uv data, particle data etc etc). The mesh data doesn’t even need to contain any vertices/edges/faces