It depends on the sailboat configuration. The stemhead are sometimes sufficiently ahead and sometimes a bowsprit is recommended to prevent from interferences with the rigging at the head of the mast.
The bowsprit globally moves forward and protects the Spinnaker from the balcony, the stem and the Mainsail that shields it from the wind. Therefore, this is a recommended solution. To avoid any bowsprit distortion it is necessary to fit a briddle in case of the use of a Code Sail/Gennaker.