Honestly, being able to see (and feel) the effect helps you to understand how best to use them safely. Its not a training video as such, its a video of people being trained in the use of one. Think of it like military training where you go into the tear gas room and take off your mask. Gotta experience it so you know how to handle it. Its easy to TELL someone what will happen, but some things you really have to experience it directly to understand.