From 2015 to 2019 the Argentina peso was fully convertable - there wasn't any currency controls.
When you remove currency controls you need to convince the public that in fact they controls are gone for good and never coming back. Such a thing was done in my home country in the mid 80s, and we have had a much more stable currency and economy since.
Left wing government -> currency controls
Right wing government -> currency controls removed
As they say, the world has developed nations, developing nations, Japan and Argentina.