Yeah it is one of those things that those a little more in the know than the average traveller can benefit from, like some of the fares quirks, split tickets, rangers/rovers, etc!
I think that comes back to my case-by-case suggestion above. Some stations, like many in the SE England, are mainly commuter stations; whereas the North Wales Coast Line, certainly for a few months of the year, is as much tourists as it is people heading to work. The problem is if you board at Rhyl heading to Llandudno for your holidays, you could get a 2 coach TfW class 197 service, or a 5 coach Avanti class 805 service. If you get a 5 coach service one year, stand further down the platform, then next time it's a 2 coach service and you stand further down the platform and then end up walking back up the platform to board, you're probably going to give up walking down the platform because you don't understand the system.