To be honest, I don't know if this actually got used as a promotion, but as to what a promotional video can look like, one cannot get much better than This one.
As you can see from the replies in that thread, people liked it.
As to whether to purchase AnimationLab, obviously it depends if you have a use for it, i.e. will your presentations look any better with some animation. or are they better just static pictures. Most of the movies I have done are for pleasure, I did a few little ones for work years ago (I'm retired now), but none of those are on youtube.