Thank you for your reply @FrancoisIonic
But I am confused: why is there the option to build for platform “browser”. I understand the native plugins would not work with ionic serve, but they should with ionic cordova build browser, right?
I thought this was the way to create PWA-like apps. Not all plugins were compatible with the platform browser, since browsers do not allow access to all native features (like bluetooth, for ex.), but they can access the camera (which is the only hardware needed for the QR scanner).
This is kind of disappointing and misleading about the “browser” platform… :-S
In the meanwhile, I will try to bypass this using pure HTML5/JS qr scanner, but I think I will have some troubles because they usually rely on jquery and their own js libraries (not integrated into ionic). I will make a new post in the forum if I get stuck…