Why do coins have raised devices?Because the die has voids of the design below the surface of the die. Thus the coin when struck will have raised devices where the dies are showing a void of the design.
Why do fields have raised areas? Because of the dies, the outside part of the die is the fields. Thus when they polish the dies, the fields are altered. If there is a scratch/dents/cracks/gouges/chip on the fields, it will show up as a raised area on the fields. Note on this coin the area could be one of the things mentioned, but is not as deep as the devices, as they are taller on the coin. So something lightly affected the fields on that area.
Incuse marks on a coin are damage to the coin.

Incuse marks on a die, will show as raised areas on the coins struck with that die.