I couldn't agree more. Decorating the vivarium is really done for our own enjoyment, ie making the habitat appear more natural etc. The snake only really cares about a secure place to hide, food, water, temp and humidity as mentioned by Adam. That doesn't mean that it's wrong to place other items in the habitat, especially if it is pleasing to you. Just make sure that what you put in is safe for whatever lives there.
Pax
Cujo