My T hugs me at the end of every session for pretty much the same reasons your T holds your hand - he has said as much, and he tells me to pay attention to how I feel when he hugs me. I haven't read Love 2.0, but I did read A General Theory of Love, which I think says much the same thing. It has been proven that new neural pathways form in the brain with new experience.
Of course there are risks, but that is true of any relationship. It takes a skilled T to manage the right level of closeness. They need to be very attuned to themselves that they don't try to give more than they are capable of. But we need to be able to trust in their skills too. It's not easy, not easy at all, but it is worth it.