You certainly can log in using a QR code. In your business central, navigate to the Warehouse Insight Installation Report. Using this report will generate a download barcode, a configuration barcode to setup the scanner with your location, and a login barcode to sign in with.
Be sure when filling out the options that you fill in your web service access key, as found on your user card, as this will be your password to log into the warehouse app with.
Hopefully this works for you, but if you need more assistance don’t hesitate to reach back out.