What it had was a currency it does not print (US dollar) and for which there is an ongoing international shortage.
What El Salvador got with Bitcoin was yet another currency it does not print and for which there is currently an international surplus.
The thing the article does not mention, and the only reason the policy made any sense, is that ~50% of Salvadorans live abroad. So there is a substantial remittance market in El Salvador relative to GDP. Allowing remittances to flow through bitcoin cuts out companies like Western Union who scoop from the top.
Even so, this scheme only makes a little sense. A better approach might have been for the government to have set up a USD-based remittance program of its own.