If you only take chess lesson once a week, but rarely practice at home, you will quickly forget what you have learned in classes. For chess, many tactics or patterns may not present in a single game. You have to play many games to see them enough times and to remember them. Playing is the best way to digest knowledge.
In this process, winning or losing is not important. The key is that you see more, you experience more, and you think more. Everything becomes your intuition. Basing on that, you build up your knowledge, comprehension, calculation, and overall skill set.