Devils advocate.
The acceptance of Bitcoin as a legal tender in El Salvador will highlight to other countries that there is a replacement to the USD as the pegged currency. So in essence would it not then pose a risk to US financial system?
Mexico is thinking of making Bitcoin a legal tender. Probably following El Salvador's foot steps. The change is probably what the senators are trying to avoid because if the world economy no longer relies on USD as the pegged currency, would it not hurt US financial systems?
That's true. But then they should consider bitcoin itself as a threat and not what a country is doing. Your point makes sense though.
And I see your point.