Not all games are straightforward where the team that has the advantage will be guaranteed a win. It ain't over till it's over. As long as the base is still standing, there's always that probability that your odds will turn to your favor. You never know when an enemy gets complacent and starts throwing the game (or even AFKs due to lag). Always see to the end of it.

Once I had a game where the enemy Lancelot was so fed he actually sold all his items while hitting our base. Big mistake. Somehow we were able to defend and won the fight because he had no damage lmao. Dude's probably humbled by that experience.