Indeed, it is. Even if you want to cargo cult that without understanding it, you might get bitten because running those commands again will not do what you expect, since they're not idempotent.
You will now reply telling me how to deal with this situation, for example if I want to now listen on a different port, or how I get FTP (or some other protocol that needs "-m state" to work. The need to do this proves that using iptables is more complicated that your example.
Indeed, it is. Even if you want to cargo cult that without understanding it, you might get bitten because running those commands again will not do what you expect, since they're not idempotent.
You will now reply telling me how to deal with this situation, for example if I want to now listen on a different port, or how I get FTP (or some other protocol that needs "-m state" to work. The need to do this proves that using iptables is more complicated that your example.