There’s greater than just relevance that goes into the landing page event, though. It’s the experience. If a user lands on the page and a script breaks and that they can’t scroll correctly, that’s a poor experience, despite the fact that it’s a page about red trainers. If the page doesn’t work for mobile instruments – or is just “mobile pleasant” without having responsive design – you’ll be hit with demerits even supposing the page is in a different way perfectly fine.
Obviously, a page about a very different subject, a bland homepage, or a page that serves malware is going to get the lowest scores feasible.