Sure but that is as helpful as saying a Word document (.docx) is a valid ZIP file. The tags in Vue files are merely containers of the actually interesting stuff.
What matters for most (all?) tools is that the file is a valid HTML syntax. Most (all?) tools don’t care if the document it self is valid HTML. I don’t think I’ve used a single developer tool which stops working if I remove the <title> tag, nest <a> elements or even insert a self closing <div /> tag.