There are less privacy assurances when opening a QR code, since it can encode a URL with precise physical information embedded within its query parameters (like "table number" at a restaurant, for example). That kind of information isn't available to the typical website.

(FWIW, I actually wish more table QR codes did contain these parameters - why do I need to enter the table number in the form after navigating to the online menu? I hate these things btw...)