I don't understand step 3 in this lesson why we have to make a new constant here

Learning about returns, but don’t understand why in step 3 I have to declare a new variable.

Link: https://www.codecademy.com/journeys/front-end-engineer/paths/fecj-22-building-interactive-websites/tracks/fecj-22-javascript-syntax-part-i/modules/wdcp-22-learn-javascript-syntax-functions-0f6014dd-29e5-491d-9caa-87be9d5fd3dd/lessons/functions/exercises/return

The intention is to have a variable to receive the return value of the function call. This is common in programming so a chance to see how it is done and how it works.