Two genuinely different ways to keep a sprinkler system from freezing — one trades speed for simplicity, the other trades a chemical-solution requirement for speed.
A companion Concept Explainer already covers why dry pipe systems exist at all: certain spaces — unheated garages, attics, loading docks, outdoor canopies — can drop below freezing, and standing water in sprinkler piping in those spaces is a burst-pipe problem waiting to happen. Dry pipe is the classic fix. But it isn't the only fix. Antifreeze sprinkler systems solve the exact same freeze problem through a completely different mechanism — and that different mechanism comes with a different tradeoff, not a free upgrade over dry pipe.