Being in a National Register Historic District is an honor, and makes sense for downtown because there are more access to grants and tax credits that are only available to structures in a National Register Historic District and are used for commercial purposes, not for homes. It doesn't force owners to do anything to their buildings that they don't want to do. Work that already requires a City Building Permit will still require that same permit, and all local ordinances must still be followed. It may offer some relief, however, in certain situations: for example, certain ADA requirements for new construction may not apply to an historic structure if it creates an undue hardship or significantly diminishes its historic character. National Register designation can also be a selling feature for a property and a tourism draw.
These 2 images illustrate the new Jacksonville Downtown Historic District. Official designation by the National Park Service is expected by September 1, 2018.