W3C swears at VUE directives, is it important for SEO?

Question

Search Engine Optimization

If you feed a w3c page with View, then he swears at the directives, saying that they don't exist. Here are my possible two questions about this:
1) Is it important for SEO or something else?
2) If important, how to deal with it?

Answer 1

This naturally violates the W3C specification, but this is not important for the search engines. Search engines (especially Google) make allowances for JS frameworks with custom directives and know how to index them correctly.