It doesn’t matter what we call it “work-life balance” or “work life integration” or “work-life flexibility”. They all have the same purpose and end. All define the way to life.
Work life balance is balancing your work and life. Work life integration means blending or integrating work with life, hence making them in unison. And work life flexibility is being flexible with work goals and life goals, providing proper time to each.
All of them serves the same purpose even though they use different words.