How can 2 parties (US and Ukraine) meet and decide the financial fate of Russia- 146,000,000 people of which 99.99% have nothing to do with the war have to struggle and potentially lose their life savings over something that wasn't their fault.
Sanctions are needed to warn Russia that any of their actions have consequences that they must accept. Moreover sanctions will not kill humans, it will affect the Russian economy, but it will not kill thousands of people like Russia did.