Ask a sixth year what a course needs and they will give you a number to the point. Ask where the number came from and the answer gets vague.
It came from last August. A course had a fixed number of places, everyone eligible was sorted by points, and places were given out from the top down until they ran out. The points of the last person to get one became the published figure.
Nobody chose it. It is a description of a queue, produced after the queue had formed.
What follows from that
The number can move in either direction and often does. Add places and it falls. Add applicants and it rises. Neither has anything to do with how hard the exam was.
Matching it is not a guarantee. Where several people sit on the same points at the cut-off and there are not enough places, allocation among them is random.
Missing it is not a disqualification. If demand softens or places increase, this year's line sits lower than last year's.
What to do instead
Put the courses you actually want at the top of your list, in the order you want them. The CAO gives you the highest course you qualify for and nothing below it, so there is no tactical gain from demoting something you want.
Then make sure the list is not all ambition. Fill it out with courses you would genuinely take, in the order you would take them.
Use previous years' figures for one thing only: judging roughly how competitive a course is, so you know how many realistic options are on your list. That is all they are good for, and it is enough.
There is a fuller account of what moves the numbers in will CAO points drop.