(
Caveat - I have not yet watched the video)
There is a concept used in Theatre/TV/Movies called "The willful suspension of disbelief." Essentially, we know that rooms don't have only three walls, cars really would not be drivable after jumping over a creek, and (
most) people cannot fly. Yet, we allow ourselves to believe in these things in order to enjoy the story being told. I feel the same is true for our model railroads. I
know that with the exception of a few railroad museums, that trains do not just run in circles (
https://coloradorailroadmuseum.org/), yet that's what the trains on my layout actually do. I know that my hoppers cars are not really delivering a commodity to a customer and that no one (other than the manufacturer I bought them from) is actually getting paid, yet I run them anyway. There is zero earthly reason any railroad would build three tunnels under a river on one side of a waterfall and then three bridges on the other, but my Whistlestop Railroad has done just that.
The first bridge I ever scratch built was made from scrap pieces of wood just to complete a simple cross over - and it looked like scrap wood. I didn't like it and soon replaced it with something else that looked better (in my eye). The first trestle I even built looks...
okay... and still stands and carries rail traffic. It may get replaced in the future with a better looking model, or it may not. For now it looks good enough for me to enjoy the hobby. My NEXT one, though, will look far better and more prototypical and be much more detailed BUT I know it will just be balsa and wooden dowels and the like and the trains crossing it will be mostly plastic.
And I'm okay with that.