It's about saving time and work. Cast iron takes a lot of work compared to even plain old stainless steel plans in prep and cleaning. They are very heavy to handle and can't use such foods as tomatoes because they are too acidic.
An informal survey as to why you would use a cast iron is "it make meat taste better" and it "heats more evenly".
An informal survey as to why you would use a cast iron is "it make meat taste better" and it "heats more evenly".