I really like that airlines sell these two types of tickets nowadays, one with check-in luggage up to 30kg and one without. Therefore, if you travel you can actually save and if you really need to have big luggage up to 20-30kgs you can pay the extra.
"Premiun" airlines used and still some includes big luggages in every ticket, so basically if you travel ligth, you end up paying other peoples luggage.
And environmentally, every kilo counts when you are flying.
RE: Carry-On Benefits: 5 Reasons to Carry Instead of Check Your Bag that You May Not Have Thought Of, and One Obvious Reason