I really like what you said about the delivery of the message is key because you’re completely right - if the audience is distracted by the speaker, there is a good chance the message of the speech will be missed anyway.

It is funny you mention a college professor with a vibrant personality that caught the attention of the class. I also had a college professor that was similar - she yelled funny things, she laughed often, she did crazy things and the content she taught is some of the most memorable moments of the classes I took in person! Why? Because she caught the attention of all that were in her class! There wasn’t a student on campus that didn’t know who she was because of how vibrant her personality was.

I think this is something that can be applied to public speaking. You don’t have to change your personality or beliefs when speaking, but you should amp up the excitement and use different tones because it helps draws the attention of the audience. If you speak in a monotone voice, the audience will likely be distracted and bored and miss the message you’re trying to deliver.