Most of the cooking on this site is a browning step followed by a simmer, and thin aluminium camping pans are bad at the first half. They lose heat the moment food goes in, so onions sweat instead of colouring and nothing takes a crust. Carbon steel and cast iron hold heat instead of shedding it, which is the single biggest improvement available to food cooked on one ring.
Carbon steel is the better of the two here: most of the benefit at a fraction of the weight, and it heats faster.
It is also the pan an induction hob will heat. Induction only works on ferrous metal. If a fridge magnet does not stick to the base, nothing happens. Aluminium cooksets, which is most camping cookware, will not work at all, and this catches people out after they have bought the hob.
The trade is that both need seasoning and neither likes being left wet. On a trip that means drying it on the burner for thirty seconds before it goes back in the box, which is a habit rather than a chore.
For one-pan cooking, a deep-sided pan or a shallow casserole is more versatile than a true frying pan, because it will do the simmer as well as the browning.