Uh oh. Lol
Joking aside, traveling abroad I check one bag and I carry on a bag. I split my things in two bags. In the event that my checked bag gets delayed, I will still have clothes toiletries and other little comforts to get me on my way.
Anything of great value will go in my personal item bag and my carry-on.
Zippers are zip tied for the checked. With my carry-on, I will use plastic twist ties. Anything I may need on the plane will be in my personal item under the seat.
To be fair, my Domestic and International travels are one-stop stays. So, it is easier for me to take two bags - although neither is big or really heavy. I am not lugging bags in trains or over cobblestone, step bridges, etc.
Those who travel multi-city, multi country need to find creative ways to minimize weight of course. And, if their bags is delayed or lost, it can heavily impact and / or inconvenience them; especially if they are moving around every three days or so.
Just pack and carry whatever makes "you" feel comfortable.