While it is true that once you are certified your card may let you into any dive you feel qualified to do, there is so much more to learn. The Advanced course is designed to give you the opportunity to learn more while under the supervision of training professionals. I have been teaching scuba diving for 25 years as have been employed at a scuba training facility (http://www.visibilityunlimited.com) for close to 20 years now (I need to update my profile wow). Depending on the agency, the advanced course is designed to give you not only training but also experience in many different facets of diving. Deep, Night, underwater Photography, Navigation, Search and Recovery, wreck diving......the list goes on and on. PADI's Advanced course gives you an educated taste in what is available. If you find you really like a particular type of diving such as night diving then you will have the sample in the advanced and it is credited toward a full specialty should your desire be more (pardon the pun) in depth in the field.
The open water course does not make you infallible. No course (instructor course included) will do that. Scuba diving is as safe as you make it and continuing your education is a step further in developing a greater understanding of the sport in a wider scope. I feel that continuing education is a benefit as it will increase your level of becoming more safety conscious in the underwater world.
Sorry...got on a soapbax there for a minute. As far as the answer to whether or not you will get a new card, the answer is yes. At resorts and such having the advanced card is an indication to those in charge of the dives that you have had additional training and require a bit less supervision than a just-out-of open-water diver. The log book backs it up by showing how many dives you have done in relationship to the type of diving you are wanting to do. As an Instructor, there are certain specialties that are near and dear to me and there are those that I found I don't really like to do even though I am qualified to teach them. I am more than happy to refer those specialties to the instructors on staff who really do love the ones that I don't care for.
When you talk to an instructor ask them what types of diving they enjoy the most. If the bulk of the conversation is around some of your same interests, then you have someone special.
I commend, congratulate and welcome you to the underwater world..it is a truely amazing place.