[dmv]

Not really if you define (as Amazon would) efficiency as order throughput and cost-per-order. Humans are typically more expensive than robots per hour: robots cost upfront and then maintenance + energy, but if those sum up to an hourly rate beyond the cost of humans for a jobs that humans can do at comparable quality... you wouldn't have robots yet. Kiva exists and continues to get deployed...

To fulfill an order with Kiva, a human stands at a ship station (boxes, label printing, tape) near a fast path (door, belt) to outbound. Shelves are brought, the human picks the item from the shelves and assembles the order. That's putting the humans in the loop where robotics is harder/more expensive. Your hard fulfillment rate limit is then the time it takes the human to pick and assemble the order, plus whatever time it takes the robots to bring the shelves over. This scales gracefully (install more robots until the hard latency of order fulfillment becomes robot travel time from the farthest shelf to the human, plus human time) -- robots scale with the number of shelves, humans scale with the number of fulfillment stations.

To fulfill via Segway, you tie up a human for the entire travel time between station and the traveling salesman problem of order picking and back. Or you do as Amazon was doing in this article, and split pick and pack and allow for subdividing orders between pickers, and so on. This works (obviously) and the segway approach would likely improve fulfillment speed for pickers. But it does not save operating expense (headcount).