Around Platform event limits, the documentation currently states that the Event Delivery default limit is 50K/DAY but Event Publishing limit is 100K/HR. Note the limit is 48 times more for Publishing.
What does this actually mean? Does it mean that a huge number of Events can be published as long as nobody is subscribing to them?
As the documentation says, you don't need to worry about those particular limits. Those are for Standard-Volume Platform Events, and you can't create those anymore. All new platform events are high volume by default.
The difference between the publish and delivery is the actor of the action. For example: if a user updates a record's field to a certain value, you want the object's trigger to publish a new event that will be delivered to another implementation. The trigger publishes the event. The platform delivers the event to its subscribers.
According to the documentation :
The publishing allocation is how many events you can publish using any method, including Apex, APIs, flows, and processes.
The delivery allocation is how many event notifications can be delivered to CometD subscribers, including the empApi Lightning component. It excludes non-CometD subscribers, such as Apex triggers, flows, and processes.
The publishing allocation is higher than the delivery allocation because there can be various types of subscribers.
Published event messages that are delivered to non-CometD subscribers, such as Apex triggers, flows, and processes, don’t count against the delivery allocation.
