Buying Vistana Adventuras (the Mexican points system) or SheratonFlex or WestinFlex second hand doesn't get all the same perks, like exchanging to properties outside of your point system, or converting to Club Points to book MVC, and other stuff.

you need to do a lot of reading and match to exactly how you plan to Vacation to see if it makes any sense for you

Buying to get Bonvoy status is the wrong reason...

Where/when do you want to go and for how long and in what size unit? I can look up the Club Points needed.