The analogies were with regard to ease of use with proximity to the user. It's not about the detail, it's not about the exact direction. It's mere orientation for daily use designed to be as inherent as smell. It's simple and alternative. It's not meant to be the end-all-be-all of navigation.
Is it high cost? Of course it is, it's a small pioneering device.
Is it highly practical? Depends who you talk to. In the "First World," probably not.
On the other hand, its implications with regard to cohesion with the brain is the interesting part. It serves as another consistent point of data for encoding interactions around you.