I am not a native English speaker, so a little help would be nice. I read the ToS, and here is the quote: “...Customer may access and use the Service only for its internal business or personal purpose...” what does that mean exactly? Can I use the software for presenting my ideas, journalistic work, design philosophy in a youtube video, essentially being a presentation tool?

I am not sure if this would be qualified as a personal purpose or internal business.
In this regard, is there any difference between the free version and a paid one? A lot of software/service does not allow generating revenue by using a free version and/while streaming it.