Baby dolls generally serve as role-play, so the little child (male or female) emulates the care given by a parent to a baby. As some kids get a little older, dolls become an important prop in playing house, or playing hospital or even playing school. And they can simply become stand-ins for people, driving trucks or doing high dives off the roof, and so on.
Fashion-type dolls have other purposes. Some serve to show off how someone has collected something, either examples of the dolls or clothing and accessories for same. Some are just so you can be one with your peers. Some serve as a type of puppet for acting out fantasies or stories, and some can engender a life-long love of dolls.
When I was in elementary school our dolls served as a form of home-made therapy in that we would build elaborate lay-outs of rooms and our dolls would interact in various ways as the people around us did. I later found out our moms used to eavesdrop on us to find out what was bothering us.
As I got a bit older but still in elementary school I no longer played with dolls that way, but I began to design high fashion clothing and I would then make small versions of the clothes for my dolls.
My daughter used to have her dolls play “church” in that she would spend hours lining them up in seated rows on the carpet and then would preach at them. She also had them play school, and she liked to “teach them to swim” in the bath tub and at the pool.
My son, OTOH, started being nurturing, but then quickly learned that the best fun was to strip the dolls naked and pull their arms and legs off. I still find an occasional dismembered limb in the yard.
As far as your kids are concerned I would simply let them play with the dolls any way they want. If they begin to ignore them totally, then begin to pack them away in preparation for giving them away. However, depending on your kids, they might just hang on to them longer and come up with pleasing activities you might never have considered. Whether you find dolls fun or not doesn’t matter. You now have the real thing in the form of your children, and your children, although sharing part of your genome, are very different people than you and will choose their own paths out of the many, many paths you expose them to.