Vienna is Austria's capital: Schönbrunn, St. Stephen's Cathedral, the Ringstrasse museums, and a café culture that is part of the visit. The historic centre is UNESCO-listed and easy to walk; palaces sit a tram ride out.
It is a long EU drive from Pomerania, usually a planned city break rather than an impulse day trip. From Gdańsk you cross much of Central Europe. Transfer makes sense for families or groups with luggage.