I use carbide on my table saw, some of my band saw blades are carbide, and most of my router bit are carbide.
I use almost nothing but HSS in the metal shop.
The reasons are simple, I can use C4 in the wood shop and C4 can be made sharp enough to give good results, and I can cut a huge amount of wood before it need to be sharpened. That said, I invested in some cheaper blades after hitting a mineral inclusion in white oak with one of my Forrest saw blades.
The C2 or C3 used in metal working is not especially sharp, does not like interrupted cuts, and most importantly, cost money.
I tend to tweak my cutters for rake and radius a lot depending on what I am doing to get either a better finish or a faster rough. Not only do I not want to invest in a large assortment of inserts for different jobs, I don't want to have to be constantly replacing them.
I just got done machining some cast iron. I would have had to spend money just to rough cut it since the rough cast will destroy about any tool. I just put a nice big radius on a piece of HSS, took 0.060" DOC's to near size, ground the radius back to something small and took light cuts to finish. I then used the same tool to cut some tool steel few minutes later. That 1/2" HSS blank cost a quarter the price of a good insert, and will last me years. I don't hone my tools, I go right from grinder to machine (120 grit white Norton stone), it probable takes me as much time to touch up my tool as it takes me to get a fresh insert out the box.
Seriously, I could buy an entire machine for the cost of a good assortment of insert tooling and holders, and then I would have to be constantly investing more good cash on replacement inserts.
