1. It teaches the 3 year old how to tidy up the room. Better him than you.
2. Hopefully, since you are starting early, it will develop into a lifelong habit.
3. Maybe he will think twice before trashing the room if he knows that he will have to clean it up.
4. Few things warm up this mother's heart like her son's offer to clean up the mess he didn't even make. True story! It could happen to you too!
5. He actually does a decent job doing it.
6. Even though you don't really know what happens to half the things he picks up (trash can? laundry hamper? some forsaken drawer? the space between the wall and the crib? - stay tuned, the answer might surprise you!), at least they are not in the plain view and no longer an eye sore.
There's only one con on the list, but for most it might outweigh all the pros:
1. Unbeknownst to you, the cleaning genius in training decides that the best place for all of the dirty clothes he can get his little hands on is your purse. You discover this little factoid upon trying to pay for your morning java at the coffee stand and must rummage through a pile of dirty socks and underwear that includes a pair of your own undies in order to get to the wallet, all in front of the cashier and 37 people standing in line, 7 of whom are your co-workers... Not that it ever happened to me, just saying... But it could happen to you too...