Great idea! It inspired me to try to figure out a transition that works for me. I've played around to try to figure out how to create this transition without doing the double click method. I even tried to make some keyboard macros. However, I settled with adding a transition in each scene not from a global source.
However, as you mentioned in the video it wouldn't work correctly for for the type of transition you have there. Mine sort of 'fades to black' and triggers on scene switch, and has a garage door effect at the end. This method won't work if you desired any effect other than a fade for the initial stage of the transition.