According the the Met Museum, coconuts were exotic to Europeans and a cup made from a coconut could be used to neutralize poisons.
Image description: Tall silver and coconut goblet with lid. The bowl is made of most of a coconut, the base, stand, and lid of the goblet are made of silver. The coconut is engraved with biblical scenes, including Samson holding open a lion’s mouth. Cherubs look on and there’s filigree. There are also silver rams and roman? soldiers connecting the silver base and the top of the goblet.
Found at: The Met
I doubt it. Hollowed out coconuts are pretty durable and washable, and I doubt this was used for every meal. Maybe just on occasions when the owner wanted to show off.