The goal decides the format
If your primary goal is leads from WhatsApp/calls, a single landing page is often the fastest path to results.
If you need trust-building pages (About, Services, Work) and want to rank for multiple keywords, a multi-page website is the better long-term asset.
When a landing page is enough
You're running ads or promoting a single offer.
You want a clear CTA (WhatsApp / call / form) and fast launch.
When you need a full website
You have multiple services and want to rank on Google for each.
You need credibility: case studies, testimonials, FAQs, and brand story.
A practical approach
Launch a landing page first, then expand into a full website as you validate offers and collect real customer questions for SEO-driven content.