I have been a weight lifter for 20 years, practiced BJJ and dabbled in Yoga. Yoga practitioners really are not strong by any measure. It's a terrible form of exercise, although it is good for improving flexibility which is good if you take part in sports which require it.

Yoga poses that appear to require strength are simply balancing with locked muscles. You have to be light and flexible for such things, but it doesn't require any strength.

You become strong at doing what you train at. If its traditional strength training, then lifting weights is going to make you stronger in lifting and carrying things.

You are only going to gain so much strength when lifting or moving parts of your body, until you will need to focus on lifting heavier weights. There's nothing wrong with that at all as it's not everyone's aim to have huge muscles.

At the end of the day in Yoga you are still lifting or holding something, it's just your own weight.