Ask HN: Why do QR codes need so much visual real estate?

I am working on a small read-only display and I want users to open a link on their phone to read more.

QR codes work, but even small ones end up taking a lot of space and feel visually heavy, especially when the link itself is very short. Why is that? Is it because of how cameras detect QR codes, error correction, or the way the standard is designed?

Have people tried more minimal scannable alternatives, or is QR already close to the practical limit?