We believe in the Free Software movement where using software comes with certain rights, but also certain obligations. Use of open source licensing gives users four primary degrees of freedom when using Qt applications or devices:

The freedom to run the program for any purpose

The freedom to study how the program works and adapt it to specific needs
The freedom to redistribute copies so you can help your neighbor
The freedom to improve the program and release your improvements to the public, so that the whole community benefits
The freedoms are non-negotiable and absolute, the freedoms cannot be enjoyed selectively or partially, you also need to pass them to your users.
The Free Software community has thrived because of these rules, but there are also developers who never intend to observe or cannot comply to these rules, and thus should get a commercial license. The Qt Company exists to support both sets with the dual offering.