To put it in context: What is orientating yourself using the sun's position to a compass? What is a compass to a GPS in your phone? What is a GPS in your phone to an integrated sense on your very own self?
A compass is more precise than the sun. A GPS gives location along with lots of other detail and is normally included with a map giving you your exact position, and the direction for you to go to get somewhere. This one doesn't really provide any benefit over the GPS, does it? Outside of the "poetic" stuff about "knowing your place in the world~" it's a device that gives little value for high cost.
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.