Deer definitely use swampy areas. Knolls or "islands" in swamps are great bedding areas, assuming deer can get to them easily enough. Pressured deer will often retreat to such areas.
If there is much water, deer will skirt the edges. If there is food in there, like swamp white oak acorns, the deer will be in there and won't need to come out. I like to stillhunt, and swamps are great for this. Usually, knee high rubber boots are enough. Some guys do use waders, even if it's just to get to a stand without spooking deer.