... In the 15 years since then I've gone all over the world with just an 25-liter backpack. The biggest benefit I enjoy was the freedom to move from place to place without being tied down to a hostel/hotel/town just because "my stuff is there."
Oh and it's a lot easier to sprint through an airport to catch a flight when you have just a small backpack.
For example here's my packing list for a trans-siberian rail journey (which I would've missed if I had to wheel a suitcase as I ran through the airport): https://www.gregkogan.com/journal/russia-trans-siberian-rail...
An interesting side-benefit I've observed: When you return from an ultralight trip, you realize just how little stuff you need to be happy. All the crap in your closet feels more than enough, if not excessive. So you end up buying less step or even donating a bunch of your existing stuff, thus lightening your life overall.