sgarzare

Yes, I see your point and agree that NVMe can be used for the same purpose. But several HW vendors have implemented virtio-net devices in their SmartNic and may find it convenient to support virtio-blk to reuse most of the building blocks.

As for vhost-user, it's perfect for VM use cases, but with containers or applications in the host, it's not easy to use. Whereas, a vDPA device (HW or SW) can easily be attached to the host kernel (using the virtio-vdpa bus) and be managed with the standard virtio-blk driver.