That's what matters if you're an Indian with an I-140 dated 2009, afraid to change his H1B job, despite salary or personnel issues. (Also, ask me about why I'm not starting up).
That one section prevents this "you can quit anytime you feel like" threat held over Indian employees by employers, because an I-140 for the employee is issued to the employer.
An employee with mobility between employers is no longer forcing the wages down.
That does not prevent a company from sending the same job to India, because it suddenly costs so much, but it does prevent the lowering of wages due to people putting up with abusive or near-illegal employment practices.
This is good for the local economy and basically makes an "outsourcing" employee irresponsible if she doesn't jump to an american firm who will do her paperwork right.
Raising the salaries all around.
(delete mini-rant about living expenses and salaries - increased pay all around isn't always what it's cracked up to be)
That section alone, shifts the balance of power between an employer and an H1b holder.