TL;DR
Next.js 16 brings cache components, native View Transitions, and a smarter image pipeline. For business websites, the headline is faster perceived performance with less code.
What changed
Next.js 16 promotes Cache Components from experimental to stable, deprecates the priority prop on <Image> in favour of explicit preload + fetchPriority, and ships native View Transitions across route boundaries.
What to do about it
Migrate your hero images, drop priority, lean on generateMetadata for per-page schema, and use Cache Components on anything that does not need to change per request.
What to ignore
The "is React Server Components ready" debate. They are. Ship.
Bottom line
If you are still on Pages Router or Next 14, the upgrade is overdue. If you are on Next 15, take a weekend.