In point-to-point a sender and a receiver of a message have no timing dependencies. In publish/subscribe a client can consume message only when it is active (subscribed to message).

In publish/subscribe messages are not addressed to consumers.

In publish/subscribe the system does not take care of delivering messages to each client.

Point-to-point does not support message expiration time.

In point-to-point message has only one consumer but in publish/subscribe - multiple.

There is no difference from technical point of view. All the difference is how
many users have access to messages.