The app is free to use, but I invest literally hundreds of hours of work into it. While I like contributing to the community, this is a huge amount of my time and effort. In order to be sustainable for me and my family, I rely on donations to compensate for time spent.
Donations allow me to dedicate time to this project and make it what it is today. Without some compensation, I just couldn't afford to put forth the effort required to make this product.
I am very thankful to everyone who is willing and able to contribute to this project. By doing so, you keep it alive and available to thousands of users, without advertising, user tracking, or other anti-user tactics extension authors use to make money. I like this model, and I hope it continues to work!