[audiodude]

To me, it makes sense that "Give me the active/main/primary account", when multiple accounts are signed in, is inherently ambiguous. Which account is the main one? You suggest Accounts.first. Is that the first account that was signed into 3 years ago? Maybe you don't want that one then. Is it the most recently signed into account?

The designer of the API decided that if you ask for "the single account" when there are multiple, that is an error condition.