Energetic practices work well to set up the conditions for stillness. But the meditation practitioner is advised to cultivate mindfulness at all times, to understand that the state of stillness is our natural condition. The practice of meditation and and any of the various preliminary practices help to pull back the veil that hides this fact. So the experienced meditator may be able to drop into this natural state at any time, or better, to abide there all or most of the time. But that doesn't negate the function of energetic practices. Depending on the specific practice, we can still heal the body, harmonize the nervous system, increase martial skill, improve attention, etc... with energetic practices. In short, they can be utilized independently of one another, or as complimentary practices.
Further, there are richer relationships between energy and spiritual practice that tend to blur any sense of separation, but are beyond the scope of this short blog post. These are not to be ignored, as advanced practice can open possibilities that are hard to imagine and even harder to describe. While we can utilize these practices separately, we also learn there really isn't any difference in an absolute sense. This is where an understanding of Taiji (Yin-Yang) theory comes into play. One can't have movement without stillness and vice versa. So it's ultimately not a question of movement or stillness, but a concern of the quality of a balanced, holistic practice.
Understanding the basic usage of internal energy and the relationship between energy and stillness is fundamental Kung Fu, or basic skill development that we need always nurture. As in all practice, to advance we should always work on the basics, as that is where the real skill lies. As we advance, working on basics shouldn't be redundant or boring, but revealing and reassuring. If we look, we may notice that yin and yang are not separates but different phases of one continuous process. In the end, it's all Qigong.