The Butt joint is just faster for me then a scarf joint. the Scarf joint is harder to install solo. if I am worried about the joint opening up I will take 1/4" MDF and glue/staple it to the back of the joint...there is no way that joint is moving then...
That butt joint is quite visible. After painting, I don't want to see any joint anywhere.
That joint is without paint and with out any prep...some sanding it will be gone...most of the time the paint crew that follows me will sand the joints, prime them with oil, and sand them again with 220 before they paint...joint is 100% gone at that point...
Here is a painted butt joint at my folk home, my father did the prep and paint, so it was not as well as a paint crew... you can see the joint in the photo b/c I but the camera right on it with the flash. In normal viewing light you have a hard time seeing it, and if you didn't know where to look, forget about it.