I find both smokers and blast furnaces largely useless because of their highly limiting nature. They are more expensive to build than regular furnace, offer no fuel advantage, and if I want to smelt stuff 2x faster, I can set up two furnaces instead of one. Heck, early game I will usually set up a wall of 8-10 furnaces at the base to use concurrently.
Later game when I build a 16-furnace smelter, it really pumps it. I can toss in sand, ore, meat, potatoes, cobble, stone, cactus, wood and what not, and it will smelt them all - fast. Heck, once I build an iron farm, I hardly need to smelt iron anymore. My biggest volume smelts are glass and stone(until I got silk touch)
Butchers are indeed fairly useless, so I never bother with smokers. And I use blast furnaces also only to make armorer villagers.
Campfires, I don't dig either. I can toss a stack of pork in the furnace along with several coal or wood and go about my business, building, mining, whatever. I can come back 10 minutes or 30 minutes or an hour later and the pork will be all cooked and waiting for me in the furnace. With campfire, I have to stick around, adding raw food manually and collecting the cooked stuff as it pops off. If you are the kind of player who puts stuff into furnace and then sits there twiddling thumbs watching the arrow fill up, I suppose campfire makes some sense.