I did buy a really cheap frame bag that I can put on my Nomad. I did use it as a day pack to hold extra water, tube, tools, etc on some day tripping while I was pretending that my Nomad was a mountain bike. See photo. And my handlebar bag is not much smaller than the roll of stuff they usually hang from their handlebars.
But while I was out doing that, I was car camping. I met several bikepacking groups that were trying the bikepacking thing on the same trails that I was day tripping on. Every single group of bikepackers I met had run out of water before they made the destination or had to take a detour during the day to get more water. A couple of them looked dangerously dehydrated and one of them I gave some water to even though he was less than a km from a clean water source because I was not sure he would make it that far. The ones I met took the ultralight thing to an extreme that I thought was bordering on unsafe.
The bikepackers I met loved that experience. I however would have been cold, hungry, thirsty and quite unhappy. To them the biking was the experience. To me, using a bike as my transport was part of the experience too but enjoying the location when off the bike was a key part of my experience. To them, the clothes that they wore on the bike was totally adequate. To me, I like to change into clean clothes after I make my destination. If you want to minimize your weight so much that you have a large cup that doubles as a pot and a spork for your entire collection of cooking and eating utensils, bikepacking is for you. But if you are like me and want to eat with fork and separate spoon while you can drink out of a mug while using a separate bowl or plate for your food, then you will be like me and put your cooking gear in your heavier panniers.
I can understand the bikepackers, but I have different ideas on what makes a trip enjoyable.