You can see on the gamepage that it says Black wins by cancellation, same in the history, and it’s crossed out because it’s annulled.
More or less. My guess is that it’s a way for people to take a break from the ladder and not lose their place by too much. They do lose their place in the usual sense, anyone that challenges gets the win from cancellation, anyone normally jumping over them jumps over them.
But when they want to play again they don’t have to start from scratch. I guess it gives people a chance to go on vacation, or if another round of some correspondence tournament starts out of the blue, as tends to be the case, they can reject any more ladder games without too much penalty etc.
This mechanism has benefits for the challengers and the challenged.
Them cancelling the game at the start saves the challenger time, allowing the challenger to climb the ladder more quickly (not having to play a full game that could take many weeks/months to earn that higher spot on the ladder).
Also, it quickly frees up a challenge slot of the challenger, much more quickly than if the challenged player plays half a game and then resigns/times out.
Also, when the challenger is much stronger or much weaker than the challenged player, the challenged player may cancel to opt out of playing a very lopsided game, without dropping out of the ladder and without potentially messing up their own rating or the rating of the challenger.
And if someone cancels all their ladder challenges, their place in the ladder gradually drops lower and lower, more quickly than if they kept playing long games and lose those in the end. So it’s not entirely with impunity.
So in my opinion, this ladder game cancelling mechanism is well thought out and reasonable, and beneficial to the large majority of ladder players.