I dont see how would it be a flaw of visa, but according to the Taler FAQ this is a feature.
Can I send money to my friends with Taler?
Taler supports push and pull payments between wallets (also known as peer-to-peer payments). While the payment appears to be directly between wallets, technically the operation is intermediated by the payment service provider which will typically be legally required to identify the recipient of the funds before allowing the transaction to complete.
I don't understand their aversion with JSON, but holy shit all the rest is miserable