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.
That makes sense. Not everybody is interested in the spiritual side of things. I don’t see any harm in using physical exercises or basic meditations simply for health improvement though. Fitness and good health are positives for anybody even if that is all they want. That is their free will choice to set an arbitrary limit on their development.