Only purchase if you know you need the extra time to use and that Club points are the right product for your usage. If you haven't already looked into resale weeks, then look at whether that, plus using Interval International would be a better choice. Compared to some weeks and depending on how long your stays are and in what season, club points can be an expensive way to book.
Club points have Right of First Refusal (ROFR) on them so it can be difficult to judge what price will get through that process so you end up with a purchase, so it can take some time and several tries to get a deal done, but the cost saving is well worth it. You can look up rofr.net to see what prices people have reported as passing or not passing.
To get the club points to work just the same as the ones bought direct, you need to pay MVC the initiation fee of $3 per club point (min $3,000) so buying less than 1000 doesn't usually make sense. Once you do that they work just the same as ones bought direct.