When I was an undergraduate student majoring in drawing and painting, I was very troubled by this question. I had no money and was acutely aware of needing a paying job once I graduated. But the field of study that I had chosen was "art for art's sake" meaning that I was truly interested in trying to find why I wanted to make my creations; they were usually class assignments like any other assignment for learning.
I came to see that my arts major was actually no different from majoring in business or math since those students were trying to find "business for business" sake or "math for math's sake". We were all investigating a field of interest to find our place within it.
Most people know enough about art history to have heard of the Impressionist movement and the criticism those artists endured. But their investigations of color and light were "art for art's sake" and served as a new way to see the world.
"Art for Life's Sake" usually refers to the idea that the world and people in general might need inspiration beyond their everyday routines. When I was young, my father told me that I would be "an educated idiot" if I majored in Art. Well, I did major in art and have gone on to teach, be a Highschool Principal, tutor and write arts and culture articles for a newspaper. I tried to get some of my interest and knowledge about the Arts out to others and they have come back to thank me many times.