I definitely agree with the "light flick", I think it will make learning difficult stuff this year much easier if I've already been exposed to it. But also, I'm most drawn to the exam/SAC tips and tricks that lectures like these offer that I wouldn't be able to figure out myself. But yeah, it's quite a hefty price tag for those tips and tricks! :/
Again, speaking anecdotally (and I'll probably end up giving you unsolicited advice here too

), but for me, the most useful SAC tips I ever received were from the Bio teachers at my school and also friends who had already completed Bio. If any Bio teachers at your school have marked end of year VCAA exams, they can offer some of the best wisdom - important keywords to include, a list of techniques to follow for answering each question, etc. (and these are very applicable in SACs).
It takes practice to see the little tricks and nuances in SACs, and you will get caught out from time to time (honestly, where I lost marks in SACs was making an answer too detailed and not properly answering the question - although I had great knowledge of the content, I didn't convert that into answering the question properly), which is why it's important to do practice questions (Bio is actually the only subject I used Checkpoints for).
But, if you feel that this lecture will give you an edge, then go for it!

That's a really interesting point, why do you say that? Would it be because those people rely only on the notes they buy? I had the idea that having several resources on hand provides you with a really comprehensive info bank to make your own notes/do practice questions from (I'm typing this with a subject like Bio in mind!).
Not heidi but I think it's because some people buy notes and then use that as an excuse to not pay attention in class and properly learn the material, because, y'know, why pay attention and work hard when someone has already done the hard yards for you? Of course, not all people do this, and I think notes can be great particularly when you're revising something and just want a quicker overview of it, or if you didn't properly understand something in class and want to view the material in a different way/from a different perspective.
I had the AN notes for Chem and they were a lifesaver during the year for exactly these reasons - I could fill in gaps during exam revision and see a condensed, simple explanation of stuff I hadn't fully understood during the year.