Hey Steffi,
Since these tests are done early in the product cycle (on low fidelity prototypes), we do not really have customers who have tried and not converted. And thats the best thing about testing on CanvasFlip.. You don’t really have to wait for initial bad rating on the play store to iterate on your designs..
We choose users for the test from our user base who will be interested in using the upcoming feature or product.
I strongly recommend you to test your designs if you haven’t done them yet! Now that we do it, it’s unimaginable to go ahead with a project without testing them.. Glad you found the blog interesting :)