Cast iron fans will defend it to the death. But here's the truth:
It rusts. Leave it wet for 10 minutes, you're scrubbing rust.
It reacts. Cook anything acidic (tomatoes, vinegar, wine), the seasoning breaks down.
It demands maintenance. Hand-wash only. Re-season regularly. Oil after every use.
It's heavy. 10 pounds of iron for scrambled eggs? Your wrist knows it's not worth it.
Cast iron works—if you have time to baby it. Most people don't.