There are wallets out there you can buy that have Tile built in. I have a Tile pro on my keychain that helps when I need to find my keys, which is like, never.
However, the concept of what Tile can do is really great but it has needed a first party hardware manufacturer to get the thing off the ground. If people don't have the Tile app, they can't help you find the Tile when they're in range...but if that were a native API, which is what Apple has been doing with all of its hardware for the past couple of years, then you could potentially put Tiles in anything you think might be stolen. I experimented with putting them in my guitar cases at one point, you could probably squeeze one inside the seat post of a bike too.