Don’t they also use yoga only for its physical benefits in India as well though? I know it is broken down by different names for different levels such as hatha yoga for the physical aspect. Even there not everyone uses it as an aid to the spiritual path do they?
What people do now is all over the map. But in ancient times, yoga was practiced as a method of helping the body and mind become fit and “tamed” so as to function better not only in this world, but to be able to focus on the Supreme Godhead with less distraction.
In ancient times nothing was divorced from the spiritual aspect. The Vedas have many paths but they all lead in the same direction; not all lead to the ultimate, because not everyone wants the ultimate. But even going in the right direction is good; and one step leads to another. The ancient Vedic civilization was a God-centered civilization in all respects, one way or another.
Much of the stuff that comes out of India, or westerners that go to India, is not very traditional. Some is, some isn’t.