I haven't seen the video, but I'm relatively certain it'll be a waste of your money. It'll probably just tell you how their tool can make a head map and tell you to disable the heads for the damaged surfaces.
If you can see damage, trust me, you are wasting your time. But, hey, if you boss wants to toss $300 on a chance of finding some gems, go for it. Let us know how it works out. I've certainly wasted more money on data recovery training materials that turned out to be nothing but a good laugh. (point-in-case HDRC training).
Also, when they talk about platter cleaning, I think they are referring to cleaning off fingerprints and that sort of thing. Not cleaning off scratches.