I've (short) toured with my 21 lb all-road/gravel bike, which is what made me decide to invest in a purpose-built touring bike (I have had two previously, in succession). I get the attraction of minimalist bike-packing, but for on road long touring, front and rear racks and panniers have significant advantages. I have an ultra-light tent, sleeping pad and bag, but for me this is more about volume than weight per se.