What is the downside of QR codes?

The main downsides of QR codes: they exclude anyone without a smartphone (or with a dead battery); static codes suffer link rot — if the destination page moves or dies, every printed code becomes a dead end; scammers can sticker over legitimate codes to redirect people; and lazy implementations (huge PDFs, codes on fast-moving vehicles, tiny codes across the room) frustrate more than they help.

Each has a mitigation: keep a non-QR fallback (short URL printed beneath the code helps everyone), use dynamic codes for anything long-lived so the destination stays fixable, place codes where they can physically be scanned, and link to fast mobile pages. QR codes are a bridge from print to web — excellent when the landing experience is respected, annoying when it isn't.