I wouldn't call compressed air extremely dangerous, but more than you'd think.
It can hurt you in a lot of ways and it's often played with like a toy. Like blowing air in somebody's face, don't do that, think of it like coming at them with a handheld drill. Treat an air compressor like any kind of power tool, not exactly dangerous but can hurt you.
That video of the guy that jokingly poked his friend in the ass with one and then the friend died from it will haunt me for the rest of my days. What a way to go...