Local storage can be dangerous

If a programmer stores a lot of state in local storage - this a name value pair database within the browser, this can be a poor choice.

The problem is that as the application changes this storage can become a mess - an older version that has an data model different from the current application can leave garbage in which can create hard to detect bugs in newer versions of the code.

It makes it more likely to create problems in the field with customers seeing weird bugs that developers don’t see.

See windows registry for an example of an analogous problem with windows.

At least with local storage the customer can clear localstorage in their browser from a website.