There's absolutely no issues whatsoever with passing through hardware directly to a VM. And Virtualized is good because we don't want to "waste" a whole machine for just a file server. Sure dedicated NAS hardware has some upsides in terms of ease of use but you also pay an, imo, ridiculous premium for that ease. I run my OMV NAS as a VM on 2 cores and 8 GB of RAM (with four hard drives) but you can make do perfectly fine on 1 Core and 2 GB RAM if you want and don't have too many devices attached / do too many iops intensive tasks.