Difference Azure Queue and Topic with one catch-all Subscription?

Question

If I, in Azure, create a

• Queue

or

• Topic with one catch-all Subscription

What is the difference?

TL;DR

I know that one can add more Subscriptions later on, and I know about filtering for the Subscriptions. But that is not part of the question.

Same: There is one dead letter queue.
Same: Each message gets handled once-and-only-once.
Difference: ?

Answer 1

You're focusing on the receiving. The real difference is on the sending side.

• When a message is sent to a queue, the sender targets a specific destination. This message type is often called a command.
• When a message is published to a topic, it will be received by zero or more subscribers. This message type is often called an event.

With commands, the sender and the single receiver are coupled. With events, the sender and the receiver(s) are decoupled.