Taken literally, ‘all expenses paid’ could mean covering travel costs for guests, food, alcohol, live music, etc.
It’s better to be specific about your prizes, so something like “enter for a chance to win $ towards the wedding of your dreams!” Or, “Enter for a chance to win the wedding of your dreams!” – and then spell out exactly what is included. But stating “all expenses paid” could mean anything and everything which is why we recommend against using it to describe travel prizes.