Hard to find a market for platinum and street value isn't really known in my country but gold and silver are some of the big ones in my country. I think that this is an opportunity to buy gold now that its bull run is over the prices is slumping back, the prices will definitely go up someday and I think that anyone who passes the opportunity to buy one now is a fool.
It is not hard to find considering there are two ways to go for it, one is you do not buy platinum like directly at the streets, you go to exchanges and find an exchange that allows you to own platinum on paper, of course you will not physically own it, you will just have it on some computer screen.
Most nations have that kind of asset exchanges here and there, banks do have that too, just look for places that does it, and when the price increases you can sell it on the same exchange as well.
Secondly you could actually go and buy some, which would be not a smart move if you ask me, there is no need to hold it, none of us actually hold bitcoin in our hands neither, so it is really a bad move but you CAN do it if you want to. However after all that said and done, I do prefer gold as well, gold is something you can use anywhere in the whole world and has a good value and very easy to cash out.