From log bundle - look for, including in contained zip files too, vmware-converter-worker log. There should be an message similar to
"[19072 warning 'Default'] Device is USB, firewire, SD, or MMC \\.\PhysicalDrive1".
The idea of skipping such disk is simple - the destination hardware is not same as source one and in most cases there is no equvalent hardware on destination.
For Workstation - you not need to convert USB devices because you can use USB passthrough function.
HTH