I often find it weird that we don't have more devices powered by gravity / heavy weight, except our old school scales for weighing our bodies.
Hydroelectric energy storage is one example that is hugely successful, albeit requiring geography to help. We also use water towers in some places to maintain pressure in pipes with the hydraulic head.
On a smaller scale, it's more space efficient to use weights to store rotating energy as a flywheel.
That said, stored energy in a system isn't always a desirable property, generally it means more careful designs are needed so that the system defaults to safe.
That said, one of the oldest energy captures is a watermill. It's powered by gravity.