Good point...IF you have an air compressor AND it is handily near the spigot.Obviously it is almost 100% easier to drain the hose each time rather than hauling 5G buckets of water several times a day, so I don't get it.
If you disconnect the hose at the faucet after use and blow in it, you will remove enough water that it won't freeze solid.
Best case scenario; blow it out with an air hose on an air compressor.
And Bear Foot is right, a 100W bulb in a 3' x 3' box would keep it from freezing, but, then again, if you have to roll and unroll it each time, why not just "walk" the water out from one end to the other?
It ain't rocket science. LOL