At the first place, it is the airport that attracts people to Trapani. But when you are there once, you discover that it is a place worthed at least of 1 full day stay (or 1 night, as the nighlife is greated than expected).
There are several good ice cream shops, ideal for experiencing "granita" if you are on Sicily for the first time.
Nice place to stroll, surrounded by the ocean. At night it's very pleasant and there's good food (speciality fish and couscous).
Not many sights but still recommendable, especially if you're flying back from Birgi airport.
Very nice area, beautiful view. The Etna is recommendable!
Culture: you can find many old buildings etc. here.
Indeed, there are hardly any restaurants or terraces here; or they were full. They don't have any traffic rules and they are very preCathedrali