They are very multi-purpose – hiking, waders, warmth – I've slept in them on a 36-hour slog and that worked fine – better than most anything else for sleeping in all my clothes.
But there are heavy. And "one pound on your feet is worth seven pounds on your back" because you're picking up that weight, accelerating and decelerating that weight several times each second.
But thrashing around an Aleutian Island, not having to change into waders, nor throwing boots across a stream and dry my feet before redoning my boots, not having to worry about cold feet at night or in camp – that was worth something. On the JMT, PCT or AT, I'd use lightweight low-cut hikers and have a small arsenal of socks to vary for the situation and for any mishaps. In more extreme conditions, if I wasn't trying to do more than 10 miles day, Bogs might again be an option.
I also wear them a lot on power boats when fishing for salmon or halibut. And for clamming. And when walking on the beach with the dog in the rain. I rarely need hip boots while canoeing – usually Bogs suffice and are far lighter and more comfortable. Other times I really need chest waders (when in the surf), but between having Bogs now and always having had chest waders, I haven't used my hip boots at all in a decade.