There is this sentiment that you don't design the homepage of a site first. For most sites, it's an anomaly. It's unlike any other page and not something to base the patterns you use for the rest of the site or help inform other pages.
You might call it a one-off.1
One-offs are OK! A world without one-offs is very boring. But a site chock-full of one-offs leads to familiar problems: inconsistency and non-reusable CSS that leads to bloating and maintainers that don't really know what's used and what isn't.