When a user selects only necessary cookies, what’s the impact on services that use cookies to operate certain functions?

For all consent products, site owners will want to delineate which cookies are necessary for the website/services to function (e.g. chat, marketing automation, personalization, etc.). For example, if a cookie is necessary and is marked as marketing, and the chat service for example needs it to function, that service will be interrupted. If this occurs, updating the cookie category resolves the issue.