I went through a time last year (2013) when I was designing and building simple, single structure models with cardstock and construction paper. This is one of those models. The scale is roughly 1/24th.
Yes, interiors do add a lot of "life" to a model. They are a lot of work, however. You can spend as much time on an interior as you will an exterior, and interiors usually receive only secondary attention.
Nonetheless, you are right. Interiors add a lot to a model car.
As always, thanks for the compliment and encouragement.