Would this sleeping pad be appropriate for...
Would this sleeping pad be appropriate for snow camping?
It would definitely offer you significant R-Value, or insulation, between you and the ground. I think you would be amazed at the difference between sleeping on this pad vs. an air-only pad or a tarp. In fact, this is the most insulative self-inflatable pad you can buy! You won't even notice the cold ground with this pad. It's also incredibly comfortable. If comfort and warmth are your main needs (vs. pack size and weight), then this is the best pad available.
However, if you are planning on packing it in, the size and weight is overwhelming. The best all-around winter pad made by Cascade Designs is the Trail Pro. It's 2 inches thick, packs very small, is lightweight (2lbs), and has an R-Value around 5. This is more than adequate, using a properly rated sleeping bag, to keep you warm in the winter.
Another pad that may work that isn't so bulky (and will save you money) is the Thermarest Luxury Map. Very comfortable and very warm.
The best ultralight self-inflatable pad is the Thermarest Prolite Plus. This will require a warmer sleeping bag, but is adequate for winter use. I've used it many times and have slept very well in a tent in sub 0 temps.