A subscription tracker sits close to sensitive data - your email, your spending, the services you rely on. With a closed-source app, every privacy promise is something you have to take on faith. With open source, you can read the code and confirm it.
Verifiable privacy. Suprascribe claims it never stores email content and only scans subscription-related messages. Because the source is public, that is not a marketing line - it is something you or any engineer can check line by line on GitHub.
No lock-in. You can export your data, and because the project is open source you can self-host it entirely on your own infrastructure. Your subscription data never has to leave systems you control.
One-time cost, not a rented tool. Open source and a one-time PRO purchase go together: you are not renting access to your own data month after month. Pay once, own it, self-host if you ever want to.