[RjQoLCOSwiIKfpm]

The physical card has a chip, which is digital.

The point is that the ticket has a unique ID which is tied to the owner.

Normal non-digital paper train tickets just indicate "someone paid this" but aren't tied to a unique personal identifier.

[dathinab]

But that id doesn't get transmitted anywhere as long as you are not checked for a ticket, which is rare. (And that's not saying that when you get checked it will collect personal non-ananomized data points, it doesn't.)