This has some possibilities as a device that can be worn on your pants/belt to hold smaller items, that can be gotten to quickly.
An additional space for holding props and what not.
Not inexpensive, but it looks great. Very Batman like.

https://www.dangoproducts.com/products/c......=uniform

Be sure to click through the product photos.

Looks very slow and ineffective, since it’s a twist off. I wouldn’t want to try and subtly twist the top off, and clumsily retrieve something from it without everything else falling out since it’s positioned vertically.

I think you underestimate the value of a pocket.

My thinking exactly! Also: What's wrong with having a magnet in your backpocket and attaching things from the outside? Way easier to get to. If you wear clothes that don't conceal that kind of arrangement, the capsule will not help you, either. If you have stuff that's not magnetic and can't be shimmed, either, use a pair of these "rattlesnake eggs" (https://www.amazon.com/Magnetic-Rattlesnake-Great-Rattle-Snakes/dp/B01MTV1L4P) and just put one in the pocket and the other one outside and have your paper, cards, bills between them.