Why vinegar + water to clean stains? The advice for cleaning salt stains (for example from shoes) with a vinegar + water solution is fairly ubiquitous on the internet. Is there a chemical explanation for why the vinegar is important? Why not just water?

Edit: I don't actually know that vinegar helps clean salt stains. There might be actually be no chemical reason for the advice to be valid.
The acid in the vinegar helps to a) dissolve substances or b) makes the substance easier to remove. The water is neutral (more or less) so won't really dissolve any stain or such