Sand is good for drainage in dense soils such as clay gardens.
It is used for gardening all over the world.
Many gardeners DO NOT reccomend sand in many soil types, especially those that contain silt as it can form a kind of cement.
"clean" sand is PH neutral, but many impurities in the sand can affect your PH
also many sand types contain a healthy dose of salt in them..."Danger Will Robinson! Danger!"