The effectiveness of continuing education varies wildly. Take continuing legal education, for instance. Go in one of those and you may see a bunch of lawyers simply reading and doing other things to pass the time -- a lot of states require a certain number of CLE hours, but only demand that the attorney is present at them. Getting something useful out of them is another matter entirely.
Regardless, continuing education can be beneficial so long as the subject matter is compelling enough to keep the attention of attendants. It's more useful, still, if participants must demonstrate some kind of applied knowledge using the concepts taught at the end of the course. Otherwise, you wind up with a bunch of people just milling through classes because they need a certain number of hours to keep their professional licenses.