Valid license keys are required for the following purposes:
Validate the purchase in order to use the template/product legally
License keys are required to verify the purchase and get premium support.
It is also required while getting the GitHub repository access for any purchased item and raising the support ticket/issue.
Future updates and fixes
In the future, it may be required to install the template core packages.
To find your license key refer to the article: Where to find the license key?