A less transparent interface might require the application to know which computer hosts the drive.

The generic interfaces can be used by any backend application, but require some programming effort.

Apps needs improvement, yes, but I don't think "the interface requires practice" is really a problem over and above any other device.

The interface requires 16 signals, out of which only two can be shared among multiple PHYs.

The command-line interface requires more knowledge of the product but can be more easily scripted and automated.

Innovations that incorporate a novel interface require significant learning cost from the consumer since they imply learning a new set of tasks.

Modal interfaces require training and experience to avoid mode errors like these.

This interface will require to be written.

These interfaces require between 1 and 4 control signals for operation, resulting in a memory device in an 8 pin (or less) package.

Still, Mr. Kirwin says, these interfaces are not truly intuitive and require some training of their own.