Barbells and dumbbells are appropriately ergonomic (handles, balance, etc.) and won't ruin your back if you use proper technique. Lifting a heavy stone is a recipe for injuring yourself severely.
People need specific indoor gym equipment if they lift, which is a very valid form of exercise. Or, you know, if it's raining or thunderstorming or a humid 100°F outside.
And bodyweight exercises only get you so far, even if you're doing one-handed or one-legged versions.
You can't just dismiss the fitness routines people have spent years choosing and refining and getting better at. The fact that you seriously suggest lifting a heavy stone demonstrates you don't seem to know much about safe fitness at all.