What are the pros and cons of enabling 2 factor authentication on internal user workstations of an organization?

An organization has all the regular controls you can think of for network and systems protection from the 10 security domains. External login access to the organization's services is protected with 2 factor authentication. As an improvement on security posture, it is suggested that 2 factor authentication could be enabled on all user workstations. Given the fact that security controls ranging from physical security to logging access are well implemented, what are the pros and cons of implementing 2 factor authentication on all workstations of the organization?