Huh? Compressed air is way way more dangerous than pumped water. A pumped water disaster is a flood. A compressed air disaster completely obliterates the containment vessel and surrounding room and the overpressure wave and shrapnel are also fatal. I'm not sure how you would design a high pressure air tank to fail gracefully. The air is like a gigantic spring, and once it starts to go it's going to tear the containment vessel to shreds.

There are things you can do to make it safer, like installing the tank at the bottom of a pool or buried under a few feet of dirt, but they add complications and expense.