As the name suggests, this light is "omnipresent" and radiates its light from a single point outward in all directions. Its behavior can be compared to the light of a light bulb.
As soon as you create a Light object you can change its Type to Omni in the Attribute Manager settings. The light’s general settings, including the Type menu, are shown in the image below:
As you already know, these parameters can be used to modify the emission of light for the Light object at any time. The Omni light is suited for all lighting situations in which light should be emitted spherically. If light needs to be directed in any given direction the Spot light would be the better choice. You can get an impression of how a light illuminates a scene or objects without having to render the scene by switching to
In this mode you can get a good impression of the placement of specular highlights or how shadows will be cast, as shown in the image below.