If a scratchbuilt structure has just 1, 2, or 3 visible sides, does it matter that the nonvisible portion has been left out?
If a covered gondola coil car contains no coils, does it matter that you are simulating a full load? (same question for boxcar load that no one can see)
If your wife’s wedding ring is made of glass and looks exactly like a diamond, does it matter to you or her?
Once upon a time, I was in a train club that had pieces of a sectional layout in a members garage and he built prize winning modules in a room attached to the garage. A train show was coming up and he was building a diorama of a logging scene with a team of oxen dragging a log out of the woods. Planned to kitbash cows into oxen. But he didn’t have any scale cows. The train show was coming up in two days. He tried the local hobby shops. No cows. The shop in a town an hour away (a town famous as home of one of the world’s largest ranches.) No cows. He called hobby shops in a major city three hours away. No scale cows. He was desperate. I suggested he look on the club layout in his garage. He didn’t remember any cows on the layout. I told him to look in the stock car I had left on the layout. He said he was serious and this wasn’t any time to be pulling tricks on him. I told him to go look. He finally looked, popped off the stock car shell to liberate the cows and won best of show for his logging diorama.
Good Question! I am working on a scratchbuilt log cabin that will located so that only the front and one end will be seen. Do I need to apply stones to the back side of the fireplace chimney?
There are many aspects of model railroading that are critical to one person while something very obviously out of scale or not prototypical is let go. I think it boils down to what you want and that is the beauty of the hobby.