Mainly I think this product is good value.  Also, there is an advantage to getting active dry yeast as opposed to cake yeast.  It has low moisture content, giving it longer shelf life.  The shelf life of active dry yeast is 2 years from the package date, but it's advisable to use it within a year.  If frozen, it can last for over 10 years.  The main disadvantage is that it's more vulnerable to thermal shock than other baking yeasts.