Easy generator says, most people forget at least 75% of what they studied in just few hours. Imagine working so hard to provide an important training session to your employees only to see them forget it all the next day! Will arranging another same session help? Obviously not.
But, in elearning, your materials will remain there in your LMS. Whenever needed, your employees can get back to it and revise or get that one information at anytime easily. Along with the accessibility, the ability to create a story, videos, sounds, graphics helps them retain information better.