#3 To keep Roman Reigns out of the Money in the Bank scene
One of the most subtle reasons for WWE to let The Miz take the MITB contract from Otis is to keep the Universal Champion, Roman Reigns away from the Money in the Bank scene. The Tribal Chief has been on a whole different level ever since his return to WWE at SummerSlam earlier this year.
With his amazing heel turn and alliance with Paul Heyman, many in the WWE Universe are considering Roman Reigns to be the best character in the company right now. With that kind of momentum and the highly personal feud that he is in the middle of right now, it makes no sense for WWE to involve the Money in the Bank winner into the mix.
The Miz was drafted to Monday Night RAW recently. With The Miz winning the Money in the Bank contract tonight, he would likely take it with him to Monday Nights and try to cash-in on the WWE Champion, Randy Orton. This would make for a better scenario than anyone trying to attempt to cash-in on Roman Reigns.