Hey @Valerio Chang 👋 Jacques here from Intercom Support. I hope all is well today!
When a teammate is assigned an Inbox seat, they gain access to the team inbox and can be part of a team like Sales. However, if you remove the Inbox seat, the teammate loses access to the Inbox and its associated features, which would include being part of a team that requires Inbox access.
Teammates without an Inbox seat can still be part of the Intercom platform but with limited capabilities. They can reply to conversations through the Contacts page and use internal notes and mentions, but they cannot be assigned to conversations or use other Inbox features.
If you only need the teammate to belong to a team without Inbox access, you could assign them a Lite seat. Lite seats allow teammates to view conversations when mentioned and contribute with internal notes, but they cannot reply directly to customers.