In case you play a wind instrument or do active singing, you learn breathing which is critical to both theatre or elocution.
As a speaker, what is the most rewarding and enjoyable part of communication
Enjoyable is if you get your point across and make it effectively. If you send a wrong message, well then, you are not a good communicator. If you are communicating something, you must communicate it clearly, otherwise you really need help. This happens when you are trying to be too clever. What happens is people’s sense of humour is very different and disparate. And when people misunderstand, it means they are undermining the basis of what you are trying to do. Do people misuse communication skills? Gandhi and Hitler both were excellent communicators. I would say, like with any other skill, communication is agnostic. You can communicate good things or bad things or have good or bad intentions. It’s much like technology, it’s a tool and a resource.