I’ve used the Sure Latches on most of my gates for years, and LOVE them. Never had a real issue with them icing over-- a couple taps on the moving parts has been sufficient (I find spring-loaded snaps to be more difficult with icing, actually). If we have a major ice storm coming (for which you’d generally have plenty of advance notice), I might slip a plastic baggie over the top of the latch and secure with a rubber band, or drape a shop rag over it.
As others have said, it’s important to keep your gate posts plumb, but these latches help make that happen because whenever the gate is closed, its weight is fully supported by the latch. Eliminates the need for toe blocks under the gate. (And regardless what kind of latch, if you have a gate that’s normally left open for any length of time, it should rest on a block/tire/log or you’ll pull your post out of plumb quickly).
They’re not without complexities–as others have mentioned, there’s only about 1.5" of acceptable variation in your gate-to-post distance. But you can usually give the gate hangers a few turns to increase or decrease that gap as needed. Beyond that, if the gap is still too wide, I’ll use a spacer board bolted into the post. Not much you can do about a gap that’s too narrow.
For me, the convenience is totally worth the initial complexity of installation. Just one hand to open and no hands needed to re-close.
All that said, I would not use them with committed fence / gate testers or fencelines with undersized / wobbly posts.