Anupriya,
Yoga as only asana and pranayama is a Western popular thought and the commercialism has overblown the food and accessories to the point of mockery.
If you have Indian heritage or bringing up, you would know through experience how the principles of Yoga are sewn into the cultural fabric. Of course there is a lot to be done in every wakeful hour, time and situation permitting.
Whether Yoga is spiritual or for fitness should not be your dilemma. We are spiritual beings and only our state of denial keeps us away from it. Every step of the way, as a spiritual practice, yama & niyama (the norms of internal and external behavior) need to supplement the Yoga studio routine. Rhythmic breathing can also be carried through out the day as & when possible.
Most important is to develop concentration and absorption skills which can be acquired only through constant thought-watching, thought-tracking and thought-spacing. These skills are rewarding in the material world as much as spiritual. Yoga has all the potential of becoming a way of life. But one needs to take several determined baby steps to make that happen.