Unfortunately, this command does NOT report the secure boot status. You can only see if you configured secure boot enforcement (which requires an activated TPM).
If you do, the host will not boot if the UEFI secure boot option is disabled. Therefore the host must have used secure boot if it is up and running.
But if you did not configure secure boot enforcement, you don't get any information about the secure boot status.
I wasn't able to find any PowerCLI command or property about secure boot and no info on the web either. But you can query this at the commandline :
/usr/lib/vmware/secureboot/bin/secureBoot.py --help
usage: secureBoot.py [-h] [-a | -c | -s]
optional arguments:
-h, --help show this help message and exit
-a, --acceptance-level-check
Validate acceptance levels for installed vibs
-c, --check-capability
Check if the host is ready to enable secure boot
-s, --check-status Check if UEFI secure boot is enabled