This is still the top result for this question on Google, without a reply after 8 months, so I will link to the CyberPanel developer’s post on the feature here.
https://community.cyberpanel.net/t/how-to-use-apache-as-reverse-proxy/42940
The short explanation is that it is a feature for people who want to use LiteSpeed and Apache at the same time. LiteSpeed’s cache makes the site load quickly, while Apache is used for certain PHP-heavy tasks, such as some e-commerce stores (they mention PrestaShop).
Do you need it? If you’re using LiteSpeed, and thus most likely disabled Apache during your server setup prior to the installation of LiteSpeed, then Apache isn’t running, so there’s no need to check the box.
They say you can enable it later after installation if you want it, by following the guide in the link.