I used flax oil to season my dutch oven, and finds it stands up to frequent tomato based pasta sauces for a bout a year, but it does eventually fail, an you know immediately when that happens, iron flavoured bolognese. Did that for a few years and finally got an enamelled set for that. As for the frying pans, mine are really old (1920s) and quite lightweight, nowhere near as heavy as newer Wagner 1898s and Lodges. I find the heat retention just perfect when making a carbonara, i turn the burner off when the pasta is three minutes from done and the heat is just perfect to make the carbonara sauce cook without turning into scrambled eggs. The other use, pan frying steaks, nothing does that better. They’re not for everything, I have one 7 inch teflon pan that i use for one purpose only, and that’s french omelets. I have zero interest in trying that in a cast pan.