I would write the relevance like this, which should be more efficient:
(it as trimmed string) whose(it != "") of string values of selects "description from Win32_OperatingSystem" of wmis
This should achieve the same thing but only query WMI once.
This appears to be equivalent using a registry read instead, which should be more efficient than WMI:
(it as string as trimmed string) whose(it != "") of values "srvcomment" of keys "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" of registries