Is integrative medicine accepted? Worthwhile?

Yes. Over the years more and more medical schools have been developing integrative medicine centers, and there's a consortium of academic health centers for integrative medicine: http://www.Imconsortium.Org/ there are fellowships where practicing physicians may study, such as http://integrativemedicine.Arizona.Edu/ there is a medical board also: http://www.Abihm.Org/ these are all health signs.
Yes. Integrative medicine draws from the best of conventional medicine and the best of alternative/complementary medicine. The definition of alternative changes as modalities such as acupuncture become part of the mainstream. Integrative physicians recognize that there are methods of treating patients outside of the traditional medical model that in many cases can be as effective.
Yes. I was a conventional doctor for 10 years before going through a fellowship in integrative medicine. I can do so much more now, and really get to the root of a problem instead of just treat symptoms. Integrative medicine is the way of the future.
Integrative Medicine. Yes, Integrative Medicine is definitely accepted when practiced in an evidence based manner, meaning that there is reasonable evidence that there will be a beneficial outcome from the treatment. However, most PCP's do not have formal training in Integrative Medicine.