So, I'm seeing a lot of builds that are way, way too simple. If you have any questions on how to make your buildings more detailed, how to build this or that, etc, feel free to reply and I'll get back to you ASAP.
Since this thread is near the top, I don't think this is considered necro posting.
I mainly use wood types to emphasize a theme to my build, and to use the correct material for the correct build. Having that a lot of cabins are just a triangular set of blocks over a square box, I like adding a different color palette to emphasize a mood.
In a nutshell, I use them for realism and the vibe of my build.