Concurrent sessions for users on the frontend could be considered a vulnerability for some environments.
For example, if the credentials of a Zabbix user is leaked, an intruder could perform access from a remote location and the current user wouldn't be aware of this.

It would be nice to have some feature that proactively informed the current user when some other IP address tried to access it, or even set a limitation to block two different sessions of the same user to be happening from different locations.