The International STandard Name Identifier is supposed to help clarify who's who in the creative world. If there are 100 Bob Smith's publishing, an ISNI is supposed to delineate Bob from Grand Rapids from Bob in Topeka.
For background, see "More metadata, please!'.
Rates are cheap and one-time expenses. If you've already been published (in literary, music, whatever), you may already have an ID in global metadata and can just claim yourself.
Not many organizations are curious about ISNI, yet, but -- you never know if/when it'll take off as a standard identifier, like DOI numbers for academic journals.