The way I see it is that I'm not in a hurry to get good... if me getting good is even possible of course.
I'd rather take my time and work through it bit by bit. I guess a course such as the one described above could help but I've always worried about missing something unique that can ONLY be learned by doing things myself the long and, sometimes, hard way.
I'm happy to work with guidelines (especially for the mechanics of scriptwriting) but what if my stumblings reveal a hitherto undiscovered idea that I'd not necessarily get by following other advice?
Sure, I may not end up writing that killer SitCom (I know, I know 'it's all been done...') but I'll have a lot of fun doing so... and be £99 up.
That kind of money can get you a decent shag on a desperate Friday night!