When I traveled for a living, doing customer facing work in software companies, I kept a Dilbert cartoon on my bulletin board. It depicted an engineer, being told to fly to a customer site for some last-minute mission critical work. When the engineer got to the customer site, the customer held up a telephone and asked "Do you have these where you come from?"
Given that they do have phones in India, it's perfectly reasonable to ask why I'm traveling 7000 miles to visit my team.
I think its simple.
Relationships build results. In any team setting, you need to know the people involved. You need to have a face to put with the name and the userid and the avatar and the voice. If at all possible, you need to know when someone says, over a bad speaker phone connection "yes, I understand", whether they're saying it confidently, with a smile on their face, or questioningly, with their brow furrowed. You can't get that from IM, e-mail, or phone conversations.
Maybe on my next trip, my folks in India will point to a video conference terminal, and say "Do you have these where you come from?"