I personally don't see myself ever playing an Origin character; however, I do see why some people might appreciate their existence.

Some people who aren't entirely familiar with the D&D system might not understand how important certain ability scores are to certain classes. For example, when building a Wizard, obviously high Intelligence is recommended. But how high? Is 12 high enough? What about 14? 16? Or should it be as high as possible, at 18?

What about Backgrounds? Is it best to pick a background that matches your class skill and tool proficiencies, or a background that expands your class skill and tool proficiencies?

These are all aspects of character creation that casual players probably don't want to deal with. Having pregenerated characters (or Origin characters) allows for a click and play without requiring the player to sit down and study game guides before making a character.