A memory leak is essentially when a program uses more and more memory because it loses track of some of it so it can't give it back to the OS. You're thinking of another kind of leak.
I know a lot of people that are reading countless books, watching countless courses, getting entrepreneurship degrees, yet they can't create a single successful business. I am not saying that this 6-hour course is useless, but you may choose to spend your time actually working on your startup and produce something valuable at the end of the day.
-- Probably someone else already mentioned this in the comments here, I just couldn't see.