Transitional champion.
They had no idea what to do with Otis holding the case, so they gave it to the Miz and figured they'd find a way out of it. The briefcase works pretty well on a guy like the Miz because he's got solid mic work, can win the title cheaply without it impacting ANYONE's character, and then he can also LOSE the belt just as quickly just to transition to the next guy.
When the dust settles, Drew never really lost clean. The Miz's title reign here is quickly forgotten, and they have a clean slate for whomever takes the title from the Miz. Sounds like an ideal scenario in the end. It makes for garbage programming in your Wrestlemania build, but ultimately water finds it's level and we're good to move on.
EDIT:
This coming from someone who legitimately enjoyed his first title run when he main evented WM 100 years ago vs Cena, and pinned him.