Yoga is a fantastic workout for your physical body, but that is not its purpose.
It’s purpose is to cultivate a deep sense of connection to the present moment. In doing so it is the ultimate workout for the mind.
Sweating, losing weight, gaining strength and all those things are collateral benefits but should never take precedence over the real purpose.
I’ll go so far as to say that if your real goal is to get “fit” physically, there are many more effective and time efficient ways to do so. Start running or swimming. Do Crossfit or a spin class. There are definitely better ways to get a normal “workout.”
The real reason to practice yoga is to exercise the mind.