Smooth/Soft edges gives a rounded appearance between two facets - typically used when the facets form a 'surface'.
Hidden edges are not displayed - the junction between two facets is sharp.
Having View > Hidden-Geometry ON lets you see such edges as dotted line styles,
You can apply these properties to selected edges, but if you want all of the edges in the model to be unseen. then it's easy - make/use a style which has the edges option unchecked.
EDIT: Dave beat me to the line !
Your working style will need edges showing to let you draw and edit things but your animation scene-tabs can use the edgeless style...
