Why Villeneuve sailed to the Caribbean

What was the point of Villeneuve going to the Caribbean?

He hoped to draw British fleets away, return to link with Brest, and give his own fleet valuable experience and better handling at sea.

Villeneuve hoped to pull Nelson, and perhaps Cornwallis, into a pursuit that would let the combined fleet return and link with Brest. The cruise also mattered as training: extended sailing improved the fleet's handling and performance. Operational sea time was itself a form of combat preparation.