[ethan_smith]

The error correction is actually what enables the artistic elements - QR codes with high EC levels (H=30%) can have up to 30% of their modules modified while remaining scannable, which is exactly what these image-embedding techniques exploit.

[pimlottc]

The point of the error correction is to allow QR codes to work despite wear and tear - dirt, fading, poor lighting, etc. If you "use up" the margin of allowed errors just to make it pretty, it's not going to work as well in less-than-ideal circumstances.