When my children were little we lived in Seoul, South Korea and we traveled back and forth from Seoul to Toronto or Ottawa fairly often. I remember the ginormous suitcase, the diaper bags, the car seats (more than one), the bag of toys etc. Travel is so much easier now that everyone is grown up and responsible for their own luggage.
Secondly, travelling with one small piece of luggage that you can manage yourself means you’re going to save money on porterage.
Thirdly, while you’re tracking down a trolley or staring at the endless sea of suitcases on the conveyor belt, you’re more likely to lose track of your handbag or hand luggage and one of those things will go missing or cause you a lot of stress.
Fourthly, if you don’t have a checked bag you can stroll right past the luggage carousel straight to customs and you will get out of the airport a lot faster.
Finally, you don’t need to bring a lot of stuff. You really don’t.