It does, if you're trying to train for and simulate the feel of mountain touring with loaded paniers. When I did my transamerica ride 35 years ago, my local training area at the time, Providence RI and environs, had only some pretty small (albeit steep) hills. My training involved loading up my paniers up with 35-40 lbs of rocks and riding up and down College Hill in Providence for 1-2 hours at a time. I could not have gotten similar training in without adding the weight and riding without it - even if I rode longer, or rode harder gears. I was looking to get comfortable with handling the bike and understanding how the bike, and I, felt with 35 pounds of gear, and what it was like to ride that, both climbing and descending. Adding the extra weight is pretty much the only way to do that.