We have the Bikepacker, because the ones you roll up take too long to get into! I agree; that really matters to us too. In the Bikepackers, things stay totally dry but the panniers open fast with a couple of clicks and a drawstring. Piece of cake, honest.
"My predominant feeling is one of gratitude. I have loved and been loved;I have been given much and I have given something in return...Above all, I have been a sentient being, a thinking animal, on this beautiful planet, and that in itself has been an enormous privilege and an adventure." O. Sacks