One of my favorite idle games is not even an actual idle game. It is Diablo II that still has a community of online players. The game gets very tedious near the end of the game, to further progress and find items. That is where botting comes in, using custom scripts. Basically you design a character, play through the interesting content, and then have a program do most of the rest.
Sounds ridiculous and pointless right? But it actually is fun, to check in and find that your character mindlessly found that extremely rare item with a 0.000002% chance of dropping, while you slept through the night. You can then further refine your character by trading items online and revising the script files to improve your character, in order to reach level 99 more quickly - this takes an insane amount of actual time even for a bot.
Wait, it gets better. You can buy additional CD keys and run multiple characters at the same time. This is not my video, but it demonstrates the point:
By doing this, you get to find those extremely rare items more quickly, to arm additional characters. This way of "playing" transforms the game experience from skill to optimization strategies. Like, being a coach rather than an athlete.