Ist der 4-Fahrten-Karte im Wesentlichen das gleiche wie der Kauf von vier individuellen Einzelfahrusweise (2 Stunden in einer Richtung in einer Richtung in Zonen AB gültig), aber billiger?

Should be the same, I don’t see why would
Be different to be honest.

I always buy it since is cheaper 🤷🏽‍♂️

Yes

No. Well, it depends on the provider, but in general: **no!!**

In most cases, the single trip ticket is for immediate use. It’s usually already „entwertet“ when you buy it. In that case, you don’t need to stamp it in an Entwertet before you start the trip. But you can’t postpone your trip.

The four trip ticket requires an „Entwertung“ (devaluation) when you start the trip. It’s possible to use a multi-trip ticket for a group of persons, but each person has to „entwerten“ his/her section of the ticket (very important for „strip tickets“, but you returned l weren’t asking about these; they were common in the Cologne region decades ago, it must be punched for each person individually!). And, pretty obviously, everyone still using the public transport need to stay with the person holding the ticket.

Multi tickets can be stocked. A single use ticket usually cannot. I am not currently aware of edge cases, where a public transport provider has valuable fees depending on the time of the day (although that has been the case in the Frankfurt region 35 years ago; you could stock up on regular tickets, but if you bought it outside the rush hour (cheaper!), it was only valid outside the rush hour).

If you have a multi ticket, and the fee changes, it might become invalid. You can return it (that’s often a trip more expensive than the remaining value…), or there might be a grace period.

As a multi ticket needs to be „entwertet“, you need face Entwerter issues. Some transport providers have no Entwerter in the train or bus, only at the station (although that’s pretty uncommon now). If an Entwerter is broken, you need to try every other Entwerter you can access. Obviously not an issue with a single use ticket which is already entwertet when it comes out of the Fahrkartenautomat.