We use Creo and SolidWorks (both latest versions) alongside other systems. A huge frustration for us is when marking up files for data release or visualisation for design reviews. Many times we need to decorate a part to show colour/finish/surface finish etc and our workflow in SolidWorks is quite simple.
1. Create a new configuration (to isoltae the markup) and split the relevant faces with the split line tool - split lines are generally taken from projected sketches or surface intersections (so we can also import specific decorations onto parts for toys etc)
3. Apply topology level colours to the split entities (SolidWorks allows you to "paint" a part by topological levels - assembly part level, part level, imported body, body, face etc).
4. Export to Keyshot and render.
5. Export to parasolid or STEP and the split faces and face colours come through.
Creo has no equivalent functionality like this (in the base packages). So we are often left with the daft scenario of modelling using Freestyle and Style, then bringing these parts into SolidWorks for data preparation and pre viz work.
Aside from decorative uses like this face splitting has modelling uses in creating surface features, or simply for marking areas in the data where you might apply different surface textures to the part.