I like to recommend installing the free demo version ahead of paying for and check the necessity for session management. The OC Session Manager module is largely meant for OpenCart 3. Opencart stores some user info (language, currency, cart, and so on.) in PHP sessions. OpenCart can store this information https://rich-snippets-autom-ticos01110.blog-a-story.com/12292891/the-definitive-guide-to-opencart-backup-and-restore