Yes the Stem Cells that are in bone marrow are found in the Umbilical Cord Blood.
The Stem Cells are rare cells that are found in the babies cord blood so if you were to need those stem cells to treat cancer in your child later on then it's a good idea to have the cord blood saved and banked.
If your family has a history of cancer then it's always best to have the cord blood banked if you can afford to do so.