Amazon recently began testing a humanoid robot named Digit in its warehouses, fueling fresh concerns about automation displacing human workers. But while "robots" that walk and lift like people raise anxieties, the reality is complex.

Built by Oregon startup Agility Robotics, the two-legged Digit can grasp and move objects up to 35 lbs. Amazon claims it will initially handle mundane tasks like shifting empty totes, freeing humans for more intricate work.

The retail giant has strongly defended automation against fears it destroys jobs, noting new roles created to support the technology. With hiring challenges plaguing warehouses, Amazon argues robots handle undesirable repetitive tasks so employees can focus on more rewarding ones requiring human strengths like critical thinking.

"We've created 700 new job categories that didn't exist before robots were brought into our facilities," an Amazon spokesperson said. "Humans are irreplaceable in their ability to think at a higher level and solve problems."

Nonetheless, Digit's human-like form factors some to see it as an eventual replacement for people, versus just a tool to aid them. Its ability to fluidly walk, crouch, reach and grasp uncannily mimics human movements.

"There's something fundamentally different and unnerving about a robot that looks like a person," said MIT tech ethicist John Basl. "It's harder to think of it as just another tool compared to something clearly mechanical."

This reaction, sometimes called the "uncanny valley," may stall wide adoption of humanoid robots despite potential benefits like flexibility. Companies might turn to less controversial automation like robotic arms or automated guided vehicles that don't provoke visceral responses.

"The biggest factor determining whether humanoid robots go mainstream isn't tech limitations, but public acceptance," Basl said. "Though mechanically sophisticated, they remain in an uncomfortable middle ground between tool and human coworker."

Technical hurdles also persist. Pilot tests help robots adapt to the chaos of real logistics environments. Simply staying upright while moving is hugely challenging for bipedal bots.

"We are still very far from a future where warehouses are fully automated by humanoid robots," said Prof. Julie Shah of MIT's Computer Science and Artificial Intelligence Lab. "Their flexibility comes at the cost of speed, reliability and precise control compared to traditional industrial automation."

Rather than outright replacing humans, early applications of Digit-like robots will likely be assisting with suitable tasks in controlled environments. This "cobot" approach keeps humans in the loop at a supervisory level.

Welcoming robots as collaborators rather than competitors may smooth their entry into warehouses. But ethical concerns around displacing jobs linger.

"If we automate too aggressively without policies to support workers, it risks worsening economic inequality," Basl warned. "We need to shape an automation transition that's empowering, not destabilizing."

Carefully integrating humanoid robots is essential to unlock their benefits while respecting laborers. With thoughtful implementation, both sides can thrive. But ignoring either the human or the robot element risks unacceptable outcomes for workers.