There are a number of physical formats you can consider when buying platinum:
Governments around the world have seized noble metals from time to time, so keeping your entire stash locally could be a bad idea depending on where you live.
Safe jurisdictions like Switzerland should be considered when you get to the point of holding a significant (tens of thousands of dollars worth generally) amount.
Physical precious metals like platinum are a hedge to the traditional banking system. In a crisis, if the system collapses, it may very well take your property down with it (if it can).
If there is a run on the banks, having your platinum under your direct control means they can't confiscate it, block access to it, or have loaned it out in a leveraged fashion.
The Swiss government is unique, in that it's highly decentralized. They simply don't have the structure that would allow for a central authority to come in and confiscate property.
Because of this, they've long been considered a safe haven for metals like platinum, and the reason we recommend considering sending some there once you've accumulated a large amount.
It's important to comply with the law when it comes to buying platinum, and knowing what they are goes a long way.
Under a certain dollar amount, there's no need to declare (which may be attractive to some), but once you hit a threshold you will need to (and should) declare your holdings.