Sorry, but that's confuse. My best guess: you want to run a script that finds text with a certain style and creates hyperlinks. If that's so, to where shall the links link? How can the script know?
"Difference between cross reference and hyperlink?" - Hyperlinks are for everything outside of documents. Using them solely depends on what the export format can do. If that's PDF, hyperlinks are usually used to open web pages. Cross-refs are only for linking between document parts or other documents, also across books.