Would be useful to know the number of passengers that are entering and exit at each station. Also to know which number of passengers are present on the train at each time.
With regards to immersion, that information would not be available to a train driver in real life, so it would take away from reality.
If you want to be pedantic, on (some) modern trains, there is information about estimated passenger numbers/loading in each coach via the TMS. Although, this is usually more useful for the guard than the driver so that he/she may make an announcement about where seats are available on a busy train.
