Obligatory "I know your in Germany" first
A lot of UK train stations don't have manned offices anymore to print tickets, there are machines on the platform that allow people to buy a ticket there are still stations without one and I don't see that many people use the machines I do see. At least there is the option to collect tickets bought online at a machine if people don't want to use their phones though.
I'd say most regular users of rail travel here do use their phones, or a travel card, so I'd say thats become the norm over paper tickets here.