A quick glance when the wrist is already in eyeline is no worse than a quick glance at the speedometer or the rearview mirror. But in any case, the primary navi

A quick glance when the wrist is already in eyeline is no worse than a quick glance at the speedometer or the rearview mirror. But in any case, the primary navigatory use would be to use it while stopped at a light. (And as mentioned, it's also awesome for walking.)