I do both. The blow-out method is very effective and gets a lot of water out. The problem is, once the bulk of the water is blown out the air can blow past small amounts of water. Some water will remain, which can potentially freeze.
Once you use compressed air to blow out the majority of the water, it won't take as much RV antifreeze to get the job done, because you won't have to flush as much water out. The chances of dilution are much less.
Also, unless you drain them manually, you still have the p-traps to treat.
All sinks, including outdoor kitchen
Low point drain
Black tank flush