I’ve found that when I watch something in another language with subtitles, I find myself going by what I heard, and using the subtitles to support or reinforce sections or words I didn’t understand. I often end up disagreeing with how things are translated, or there is something said in the foreign language that can’t simply be translated. In other words, I think using subtitles as reinforcement can be useful, whereas just reading every line and not thinking in the other language for yourself might not really be helping you much.