I can't believe people are still falling for energy vaults "innovative concepts". Using gravity to store energy only makes economic sense if the costs per ton of mass that your system can store is very small. That is the case for pumped hydro where you essentially just have two lakes filled with water. A water filled skyscraper however is orders of magnitudes more expensive per volume of water than building a dam to create a lake.

Your argument appears flawed.

The mass is just a counterweight. It can easily be re-used over and over again like the weights in a grandfather clock. It can be made of almost anything. Compressed earth for example is a cheap and popular option.

The one time production cost of the re-useable counterweight is relatively insignificant compared to the ongoing economic benefit and utility of energy storage.

The skyscraper itself would presumably have other uses beyond just being a "gravity battery" in order to justify it's production cost. If not, then a building of more modest height can be used ... or no building at all --- simply create a shaft in the ground.

These options can be comparable (if not lower) in cost to pumped storage lakes and can be located virtually anywhere without geographic restrictions.

Fine. Let's do a quick calculation. You said creating a shaft would be as cheap as pumped storage. So I tried to find the costs involved and hit upon a price list for drilling wells. https://haynesandsonsllc.com/wp-content/uploads/2017/02/Pric... According to that the price for a 420 foot deep hole with a 10 inch diameter is around $30,000 Assuming we put a lead weight inside that has half the volume of the entire shaft (3.25 cubic meters) and a mass of 37 tons we end up with a stored energy of 6.5 kWh. Since the lead costs $70,000 we are looking at a price of $15,400 per kWh. Pumped hydro is around $100 to $200. If you use something cheap like concrete or compressed earth you can store 5 times less energy so you'd end up with even worse numbers. And I think it goes without saying that a skyscraper is a lot more expensive than a hole in the ground.

Now compare this to the cost for a pumped hydro storage facility. Be sure to include the cost of land in a suitable geographic location.

Why so tall? 2 building of half the height will store just as much energy.

Seems like a publicity stunt or something.