Really, as you said, it makes no difference. If there is any difference, as far as my own knowledge is concerned, Yijin Jing is more active, that is, it is mostly dynamic when doing exercises, while yoga is to put a posture to make the place static, thus absorbing "energy." In fact, they are all Buddhist things, and they also practice Buddhism through physical exercise. Its essence is the same, but it may be slightly different in the form of expression.

Moreover, the degree of exercise is different. In the process of practicing Buddhism through exercise (the so-called "harmony between man and nature"), yoga is a Sect of Buddhism, called "Yoga School", and its system is very complete. Therefore, in terms of depth and breadth, the connotation and exercise degree of yoga are higher than that of Yijinjing.

Although yoga is deeper and wider than Yijin Jing, its purpose is the same.

As far as exercise is concerned, the landlord is right.