I'll be able to explain this for you, Ok firstly the "Credits" you see in your profilve are apart of our product called "vBCredits" in which an admin can assign a number of point to be earned by actions a user makes on your forums (E.G posting, making threads, voting etc etc) these Credits can be intergrated with shop modifications such our product "vBShop" and a vBulletin.org addon called "vBplaza", vBcredits can also be intergrated into a number of points using hacks found on a variety of vBulletin Addon sites.
The "points" section you are looking at are apart of our product called vBulletin Activity, these points are earned for gaining achievements amd posting new threads and voting, But unlike vBcredits these points are not meant to be used with shops or other modifications and are souly used for calculating a users activity on the forums. a users vBActivity level is determined by the number of vBpoints he/she has earned and will determine how active the user is on your forums. I believe we plan to modify the points system in some way so that it is less confusing to people so that they don't show your points for vBa and instead remain hidden (or something around those lines). vBactivity is a powerful tool to moniter and track user activity on your forums and is a cool way to keep your members active by letting them earn certain privelidges and items (Achievements).
To sumerise: vBcredits uses "Credits" and is for shop addons, vBactivity uses "points" which have no purpose but to calculate activity.
i hope that clears things up for you
regards
-Tom