You're quite right, it doesn't tell you what might happen in the end, though repeated currency crises could happen with or without the constitutional amendment. Or, if we assume the right chose to practise the politique du pire, they wouldn't need to call on the constitutional amendment to shrink the state and destroy redistributive policies, thus creating social unrest and leading to a football stadium "stable resolution". And, unfortunately, the PP seems animated by pretty shadowy intentions.

A great deal depends on the extent to which, among the Spanish people as a whole, the C20 history of Spain, starting from the 1930s, is now felt to be a closed book - or, to the contrary, is still unresolved and therefore alive. The right has certainly been pushing the latter term. Which is more worrying, imo, than the constitutional amendment.