To get the physical name of a server (ex, when using an FCI), you need to use SERVERPROPERTY('ComputerNamePhysicalNetBIOS') ... Remembering the word salad for that property name is painful--after 18 years, I still can't keep the property name straight.

It would be ideal if this could be added to the sys.dm_os_sys_info DMV (or some other DMV with system info in it). This would make the information more discoverable and easier to query than with the (sometimes cryptic) SERVERPROPERTY().