Be aware that unless the transferred points were from a contract with the same use year and same resort as the destination contract, they will not show up in your online account. You will have to call MS to use them. This can be a disadvantage if you plan to use them right at the 11 or 7 month windows to reserve something that is popular.
If you go ahead with this purchase, be sure to verify that the transferred points were actually placed into your membership and that MS can see them. IMO, there is a good chance you will have an issue getting those points properly moved into your account after closing - it is not your common, run-of-the-mill situation.