As a side note, AFAIK WD "USB only" disks may pose a problem (in case of issues) because they (or at least most of them) have a form of pass-through encryption, i.e. the data on the disk is encrypted and is decrypted on-the-fly by a chip on the PCB, if a component of the PCB fails, recovering the data becomes very, very difficult even if the hard disk works otherwise fine.