The answer is, it depends. I did fast 1 & 2 last year just to give it a go. Consider:
1.) comfort, you are there to learn a new skill, not a how to ride a new bike IMO. The track time is limited (7 x 10 min) and you want to spend your time focusing on the exercise, not spending time learning a new bike, missing shifts, etc.
2.) If you crash (1 person did when I was there, it was quite minor), you are liable for up to $2k on damage, or pay the $129 to lower the deductible to $250. You could argue its reasonable insurance, but given you are not running 9/10ths pace the probability of crashing isn't as high as a regular track day. To me, insurance is only worthwhile if you cannot oversee a cost. i.e. would writing off a bike put you into financial hardship? what about $2k? $250? No one wants to write a check, but calculate your worst case scenario.
3.) pace, depending on what you ride, the bikes they have may be above/below your regular pace. Run at your normal pace/race lines to get the biggest benefit from the course.
There were only 4 or 5 that brought their own out of the entire class, so I was definitely in the minority bringing my own. The bike power is limited, but on nelson track just to learn how to ride, you really don't need it (although power wheelying down to 2 is a lot of fun). They have fairly strict riding/passing rules for safety. If you act like an idiot, they will throw you out, as one guy found out last year.