Re: Sinfulness
"Turning your back to your audience to look at the screen and then reading the slides out loud".
Public speaking is a skill that requires practice and effort, PP cons people into believing that just with this benighted piece of s/w they can shine and delight an audience with their pithy and occasionaly amusing slides and witty banter with the audience (the latter is of course deep into fantasy lala land).
The reality is, most casual presenters brains switch to read only the moment they step up in front of their audience.