No. You don’t have to use the storefront frontend cartridges.
For a headless Salesforce B2C Commerce implementation, you can use only the server-side cartridges:
int_algoliato import and synchronize data to Algoliabm_algoliato configure and monitor indexing from Business Manager
If you want to use Algolia’s storefront implementation, the frontend cartridges depend on your storefront architecture:
SFRA:
int_algolia_sfraSiteGenesis:
int_algolia_controllersandalgolia_sg_changes
These frontend cartridges provide a starting point for implementing Algolia search and autocomplete on the storefront.