Snapping pics over people's heads

In 2016 I went to a bunch of technical talks, none of which I intend to discuss right now, and all of which armed with a cameraphone along with everybody else in the audience. In this day of Slideshare and official corporate tech blogs many of the presentations will make it up to the web in pristine form, so why would anyone want to take a crooked, out of focus, keystone distorted, and sometimes half second too late picture of the screen?