I'm guessing you are not located in the USA and if you are I'm guessing you only deal with small businesses or never consider the 911 laws like Kari's Law or Ray Baum's Act. I know this wasn't a concern for 3CX years ago as I posted may issues until they made changes to the system.
If a 911 call gets disconnected, EMS will call back the TN (DID) they received. 150 phones ringing, good chance someone else will pickup that call, seconds count when someone is injured, having heart issues, etc.
We are required to section our buildings into zones and from there narrow down a location (east, west, floor #, shipping, receiving...) so EMS can identify where the 911 call is coming from, it also helps our internal security team, for dispatching. All phones, including warehouse analog phones, are assigned a DID. Each DID is then assigned a location identifier. This same location information is loaded into an E911 service provider and this is how the "location" gets pushed to EMS.
Perhaps 3CX could come up with a different "role" other than "user" that would apply. Or a different licensing model. Already using a 32 SIM license and our high water mark is around 4 to 6 SIM calls.