Gots yer receipt roight here, guv
These systems are wonderful ways to MAKE YOU PAY, not to make sure you get your money refunded (even from somebody else). Also: Again it's depending on some other system that is far from privacy safe, here credit cards, meaning that they now have your credit card details including name and address, and they can track your entire travel history for years to come. And all that information sits in servers you just have to trust won't leak, get broken into, have backups lost in the mail or on trains, what have you.
Paper tickets and paying cash still beat all this fancy stuff in terms of privacy, liability, robustness, resistance to fraud, and graceful degradation. The only drawback is long lines at the ticket counter, but a bit of planning might help you around there too.
Me? I'm a sysadmin, netadmin, coder, programmer, and general unix-y guy. And that is perhaps exactly why I prefer oh-so-1900s but well-understood, working solutions.