You are completly right.
Modeling is about learning the real thing through observation, documentation, ... Once this is done, you are free to do whatever you like on your layout. Some prefer to focus on the decor, others on rolling stock, or electronics, or operation.
This is where a club is handy: different people focusing on different areas will produce a great work and everybody will have fun.
Me too, I am more into rolling stock than buildings & scenery. This is why I decided to switch to IIm scale (1/22 - 45mm track). Perhaps, one day, I will do also 1 scale (1/32 - 45mm track)
Now back to the 150X: all of them were based in Northern and Eastern France. Paris was as far south they ever went. One of the problem was their size: they were designed for the German loading gauge which is larger that the French one. Hence, they were not allowed on some lignes. This is also why the have such a short chimney (not the case in Germany). TCDD could have retrofitted the chimney because the Turkish loading gauge is also very large.
On the other hand, the cab was much larger that the regular French cab, and more confortable with features like electric lighting that did not exist at the time on French locos.
The 150X were also economical on coal. The design of the valve gear and the greasing system enabled the driver to completly cut the steam when going downhill (thus saving it).
Jean-Patrick