This plugin is a smart idea but there is scope of improvement.
For reasons unknown, the developers have not mentioned here that the WordPress repository version is a demo version, which allows only creating 5 labels. If you generate more than 5 labels with the non-premium version, the labels will not bear QR code. This makes the demo plugin useless if you have more than 5 products.
Upgrading to premium version also has limitation. It does not update the stock of individual products in variable product type.
I have written to the developers regarding this issue and I will revise my review if they fix the above mentioned problems.