Yoga is mainly practiced flexibility and stability. General gym equipment fitness, can only increase muscle strength, but the body's power needs to be coordinated, so flexibility and stability is also very important. But the equipment can not provide training in this regard, so generally go to the gym outside, but also with yoga (stretching and balance), martial arts (reaction speed and balance), jumping (body flexibility and coordination), running (cardiorespiratory fitness), swimming (cardiorespiratory and body coordination), rock climbing (coordination and stability).
In fact, most of the sports we play require a high degree of physical coordination. And that's the main purpose of fitness. It's that we do the most with the least amount of force. Obviously if you just rely on equipment to workout, you won't be able to achieve this purpose. The equipment is just an aid. But a lot of people who go to the gym are putting the cart before the horse. If this is the case, going to the gym is really not as good for the body and mind as going to square dancing.