I like and share your vision of a performant, secure and reliable "open web". Thus every new tool/method that helps to get closer to this goal and to stick to best practices is a benefit for the WordPress community.

However, I'm not sure if showing the "tide score" publicly in the item description should be the way to go (false positives, etc.).

It might be a useful tool to help plugin and theme authors to enhance their code before submission. An important part will be to provide detailed information about spotted "problems" and maybe even possible solutions.