Courage is regarded as a higher virtue because it requires an ability to face danger while thinking. The signers of the Declaration of Independence had courage along with valor, two attributes that are regarded as heroic. Cowardice is regarded as the lack of courage and a higher than normal amount of fear but there are degrees of cowardice. The lowest form is a coward who lacks self-esteem. Even cowards seem to have a sense of who they are and know they have some value so they stay in the world with others. Some however lack any idea of what they are so they refuse to reveal themselves. They are psychotic. because their fears rule their lack of judgment. In the military cowards are summarily dispatched I suppose on the good riddence theory.
Unable to face life as ordinary people their fright directs their actions. Metaphorically they slither along the botton recesses of life.