As far as the hammer goes, yes on one hand it's a status symbol. On the other hand, I think the point trying to be made by Laertes is that it would be the smith's defensive weapon, as opposed to--or more likely, in addition to--a knife.
I agree that specialized tools should generally be kept in the workshop. Although it strikes me that if you could weaponize as many tools as possible--atleast to a minimal degree--they could then be used by dwarfs *inside* workshops, to defend themselves. You grab whatever's at hand, when your home is invaded.
"All you need is a table and a sharp fillet knife."
Pilsu, I don't disagree with you, and I certainly don't think you're wrong, but the problem with denying the Fish Workshop of additional tasks is that pretty soon, you realize all you need is a table (or even a log) and a knife to do everything.
It just doesn't compare well to all the other workshops. That's a problem.
Other than that, I don't think smoking or salting fish should really require a whole other workshop. Fish back then was typically eaten smoked or salted. There wasn't a good third option, unless you were desperate enough to eat it raw (which is where sushi came from). I do think that if you allow fish and meat to be smoked together (even though I can't imagine either would taste very good...), then people will do that, because it's more intuitive to do what's easier than what requires specialized knowledge of smoking meats.
I personally feel that part of the purpose of the game is to allow us players to take away something of the experience of what living in a Fortress might actually be like, and because of that, I think it's important that the game try to reflect the real facts, and guide us, as much as we guide it.
Keeping the smoked fish away from the smoked meat is only one example of that.