Nothingness: The point you may be missing is that you only resign the current game, not the entire match. In your example, resigning would mean that you only lead by 4-1 instead of 4-0. Accepting would mean that the current game counts for two.
(hide) If you want to play a game with an opponent of a similar level, you can define a required BKR range for a new game invitation. Then nobody with a BKR outside this range will be able to see/accept it. (Katechka) (show all tips)