Explain why it is useful for the pancreas cells that secrete digestive enzymes to have lots of rough endoplasmic reticulum and Golgi apparatus

The rough ER contains many ribosomes.

Remember: ribosomes function in creating proteins (i. e. enzymes) from amino acids

The pancreas functions in the digestive system by producing many digesting enzymes. The cells of the pancreas must have lots of rough ER to meet this demand.