Fortnite recently introduced bots to its battle royale ecosystem, a decision that certainly has some positive elements to it. It's also gotten people questioning their abilities and those of their opponents. These bots are not flagged as bots, instead posing as humans and mostly discernible through their odd behavior. It's led to some interesting paranoia.
Meanwhile, Nintendo has been pulling the wool over players' eyes by using similar bots to essentially fake an online multiplayer mode. Even worse, they passively advertise the game's loot box economy.
While the two games are quite different, and one is clearly more nefarious, both use bots for a very simple reason - engagement. The ultimate desire of modern entertainment, engagement rules all - and if players are engaged by an artificial sense of victory, so be it.