I can remember our engineering teacher, when we were leaving school to go out into the world of engineering saying not to get stainless tools, rules, calipers (inside and out, and odd leg), and squares. I think the reason was that the stainless, although hardened, was not as hard as carbon steel, and he did say that they won't go rusty if you are using them. I got all those tools for Christmas 1963, and still have them, the 6" rule unfortunately lost 5/8", it snapped like a carrot.
Some say the same about knives, stainless not holding an edge as well as carbon steel.
Ian S C