What Is Link Account?
When a user who has kintone license is invited as a guest to a guest space of other kintone, both kintone accounts are linked by the "Link Account" feature.
By linking accounts, it becomes possible to open other kintone to which the user is invited, without logging in again to the top page of the licensed kintone.
Also note that the guest user can use the service for free when the Link Account is activated.
Even if the guest user can use the service for free as a result of activating the Link Account, billing amount is not changed automatically.
To decrease the number of licenses for the guest user, use the "order" button on the "license management" screen of cybozu.com Store, or the "purchase" button in the "service usage" screen of Users & System Administration, and submit the order to reduce the number of licensed users.