Like anything, you have to do it enough to get the feel for it. Even using toolpost mounted cutters one can F#$% up a ferrule if you don't have the feel down for it. They also, IMO, don't cut as close to the ferrule for the smooth transition. I use a new utility blade to trim with each time, and have the lathe running in reverse as I do it. I have messed up and gouged a ferrule or two, but have also done that with a toolpost mounted cutter also, so IMO, it's 50/50. When that has happened, I changed the ferrule at no charge.
I also use the blade to shape the tip, with a tool blank in the tool holder to rest the blade on as a steady rest, if you will.
I, personally, with no disrespect meant to the video guy, use a carbide cutter in the toolpost to face the ferrule before tip placement to ensure a truely squared face for the tip. I also sand the back of the tip on a flat plate, then soak the back of it with CA and let dry. Then resand and then glue tip on and wipe excess glue before it hardens.
Haven't had a tip come off since using this method, but then again, different ways to get the same end result.
Dave