Your right that compressed air is a less energy efficient storage medium than Li-ion batteries, but only for the first couple of years. Li-ion battery storage capacity decreases at about 20% a year because of natural degradation. Consider the cost to frequently manufacture, replace and dispose of batteries compared to the wear cycles of a compressed air container which is probably measured in decades.
My point here is that the maintenance cost for compressed air energy storage is quite low compared to other options. You also have to consider the cost of making the storage devices. Steel tanks are mostly hollow and we are already really good at making them. We are good at recycling steel too. Air storage, unlike fuel cells or batteries options which consume lots of metals and require complex electronics to regulate, compressed air is extremely cheap and simple.
If our choice is cheap simple but supposedly inefficient storage of 50% via compressed air or storing 0% via other supposedly more efficient but unaffordable and unsustainable methods the choice is pretty simple.