If you feel you are confident with your knowledge of the content, have completed a sufficient number of past HSC exam papers and find that time permits, I don't see why not. Practice makes perfect. Those are sample examination questions, meaning that while they are not included in an actual HSC exam paper, the way they are written is the same as HSC exam questions, and this constitutes relevant preparation because you'd be essentially attempting the same type of questions as those in past HSC exam papers, allowing you to further boost your preparations.
I hope this helps!