Why don't we transact with securities rather than fiat money?
You've just reinvented bearer bonds. From that page:


  Bearer bonds are bonds that are owned by whoever is holding them, rather than having registered owners like most other securities. Like most other bonds, they have a stated maturity date and interest rate, but coupons representing interest payments are generally physically attached to the security and must be submitted to the company for payment.


It's been done. Like cryptocurrencies, the one class of transactions they turned out to be well-suited for was the class of illegal transactions; money laundering, payment for criminal services, prohibited capital movements, etc.

And having a fiat currency which is simply backed by a country's economy, has succeeded against all other kinds of currency as the most viable.