What does ginger lose if puréed or ground and left over time?

I know with certain herbs and spices once you cut them open or grind them they can lose aroma, volatile oils and vitamins.

I’m wondering about ginger. People either use it fresh, use a prepared version which may already have been on the shelf, or a ground one which has been on the shelf for a while.

So what is the difference between freshly puréed and ground, and/or puréed or ground and then left for a while?