I'm assuming you understand that my statements have a implicit "from an economic pov" when I argue about the practicality of pumped hydro storage, and you're arguing that it is economical to do pumped hydro on a small scale.

My understanding is that it only becomes competitive with other options at a very large scale. A 10 m deep football sized reservoir, at an altitude of 1km above the generator would have approx 13Mwh of energy storage at 100% efficiency (if my math is correct). Battery prices are around $140 per kWh, so a 13 Mwh battery installation is going to be in the vicinity of 2 million dollars.

I would love to see some costs involved in building two man made ten meter deep football field size dams, a large 1km length (it will be quite a lot longer due to it running on a slope) with all the required engineering to run it down a steep incline. The add to that the and generating equipment, and pumps.

Once you've done that, we could compare the operating costs of the two options.