Does vatnode do more than just call VIES?

Yes. On top of the VIES verdict, vatnode adds a national-registry layer for several countries — which keeps returning results for those countries during VIES country-level outages, and can enrich the response with data VIES doesn't carry (registration date, legal form, industry description). Every response also includes full VAT metadata for the company's country — the local tax name, abbreviation, and all rate tiers — so you can label and rate an invoice correctly in a single call.