I have a dumb cold weather sprinkler question for and Houston plumbing folks

Edit: oops the typo in the title 🤣

My sprinkler system has one of those backflow preventers that sits about 2 1/2 feet above the ground. It's insulated and I've already cut off the water inlet, opened the sprinkler heads, and drained the backflow preventer.

In colder climates, these pipe stands will sometimes have a port where you can plug in an air compressor to blow the air out the lines. Also, the inlet cutoff valve is usually in a box in the ground (mine is about a foot above grade).

My question is this – are the blow out ports and below ground valves just never needed here? It seems like a bad idea to have standing water in an above ground PVC line, even if it's insulated. But y'all's experience I'm sure will set me straight.