If you listen and respond to that suggestion, it can help. If you try to ignore the suggestion and maintain your habitual way of doing things, it may only become an additional source of stress. This was brought home to me by a client with a low back problem, who told me he had used one of these chairs and it made his back worse. He was tightening against the chair's suggestion to sit more erect, further stressing his back. Once he learned to relax and allow his back to respond appropriatelly, he could use the chair comfortably.
Many people tend to lean forward and slouch as they sit.
Their back stiffens to support the off-balance weight, and the slouch disrupts the natural support of the arms and shoulders provided by an erect spine. If you pay attention to your balance, and use the chair as a tool to facilitate ease and balance, it can help. This makes it sound like you can't just get the chair and forget about it. It's also true of any other ergonomic aid, like a new keyboard, dragon dictate, or one of Win's reclining workstations. You can impose more or less stress on your body in any working environment, and the only consistant way to impose less is by being aware of what you are doing.