How do you want other people to summarise your messages after you have spoken to them or given a presentation?
If you are the CEO of a company and you are giving a presentation to top managers about a new policy, it is not enough for your managers to just understand you. They have to have the ability to tell other people who work for them what your message was.
In the business world, we often think of this as the water cooler message. If someone pays attention when you spoke to them and the next day another person bumps into them at the water cooler and asks them what the boss said yesterday since they were out sick, how would that person describe your speech? How would they summarize what you said?
The real thing you need to think about here is what they think will be important in what you said. That is why it is so important to not be abstract and vague. If someone hears you speak and is unable to tell other people what your message was then your message is going to be severely limited in its impact. The most power you can have as a speaker or communicator is when your message can spread even when you are not in a room.
Anybody can be a speaker but you have to narrow down your messages to a handful and illustrate them with a story. Practice on video until you are happy with how you come across and you are sure that people will remember your points.