You may be able to get to your goal weight that way, but you may not get the body composition you are looking for. I got to my goal weight (120) by counting calories and running, but I wasn't happy with the way my body looked afterward. That is why I am doing weight training to build muscle now.
Every body is different - if you enjoy it and it's working for you, then stick with it. If you find that over time it becomes less effective, or if you are like me and decide you want to achieve more muscle, then you can adjust as needed.