If you know you'll nearly always be using the trains and/or P&R then yes, they are good value.
But how could the travel vouchers be abused by making them non-match specific ? Maybe I'm missing something, but I don't see what difference it would make just selling a book of 30 vouchers for £30, and using them for whatever match you need them for.
I'm 100% with you on this. I have two lads, and we will only need to use public transport for about 10 games. Looks like we will have to shell out £90 for three books of 30, although we only need 30 in total. Annoying.