Once you start to actually understand the game bots are a joke for simply getting an easy WotD. I learn absolutely nothing by playing bots since their patterns are so simple and manipulatable. You learn nothing in terms of mechanics because bots don't act like anything compared to people. They don't trade right, farm right, or build right. You learn nothing other than what Q, W, E, and R do.
The environment ruins any chance of actually learning. There is a HUGE reason that people who play strictly bots suck when they jump into PvP and especially ranked. There are some opponents who can't hit anything and others who have a homing beacon on your head. You only get to play against a small group of champs that don't act like they should.
Bots are good when you can't understand basics and not for when you actually want to learn a champ