My guess is where you live you could get surface freeze but nothing deep so the idea of something in the skimmer to take care of surface freeze is fine. You just have to give any ice a place to expand. Up here I get serious freeze and I just pack the skimmer with closed cell foam...same stuff as pool noodles. I've been here almost 10 years and for the previous 20 years of the pool I'm sure it wasn't taken care of the way I do it.
Think Spring.
Al