Well, I don't think you need it just for this per se
you do need the $800 Clay plan to be able to sync to Hubspot with the native integration
or you can create custom integrations via a private Hubspot app, but that'll take more time and money to build and maintain than the out-of-the-box Clay<>Hubspot native integration
Operations Hub allows you to run workflows within the CRM, but the Clay Hubspot integration doesn't need workflows to run successfully