This is a difference between the locals (or experienced travellers), and nervous tourists.
I have just come back from a trip to the UK by train. I booked all tickets online as far in advance as possible in order to get the best prices. But I know how the system works, which websites to use (http://www.trainline.co.uk), where the train lines go and I was prepared to commit to specific trains.
Nobody over 25 goes by long distance coach if they can afford trains. Trains are just so much more comfortable and a lot faster.
Overseas tourists who do not know the system, and are nervous about committing thermselves when they do not understand how it all works feel comforted that with a "pass" they can go where they want. Overseas agents are happy to sell them a pass because they make a commission. But, unless they are travelling long distances every day, it may end up costing more.
As the saying goes:; "you pays your money and you takes your choice ........"