I used to think the same. I avoided body weight exercises because I figured my body just isn’t that heavy and I need to lift heavier weights to become stronger.
What I later realized is that body weight becomes very difficult by merely changing the technique. There are a lot of body weight exercises that are some of the hardest lifts I’ve ever done.
A person who has been dedicated to calisthenics can almost certain lift twice their body weight or more. Some can even squat a ton of weight without ever hitting the squat racks.
Like I said, the strength you build from calisthenics is very deceptive. People look at you and underestimate your strength because you don’t look like a weight lifter.
I’ll give you an example, sit on the floor with your legs straight out in front of you, back straight, and palms flat on the ground next to your knees. From this position, keep your back straight, legs straight, and lift your legs up as close as possible to your chest and hold it there for 10 seconds. Seems difficult? There’s calisthenics guys who can not only bring their legs all the way up, they can do it while simultaneously lifting their entire body off the ground in this position. Doesn’t matter how much weight you push in the gym, you will never be able to do that without the strong stabilizing muscles you can only get through calisthenics. And nothing you do with weights will ever be as useful or as impressive as feats of strength like this.