What matters for a tool used on stream
A tool used live on stream needs to read clearly at a small window size, hold up under video compression, and not have distracting ads or pop-ups competing with your webcam and chat overlay. Most general-purpose spinner tools aren't built with that in mind.
Spinzelvo's high-contrast palette and large text were designed to stay legible when shared as a browser source or screen-captured at a smaller size, and there's nothing on the page that would look out of place layered into a stream layout.