I like the interface but to be truly private it'd have to be offline first like
https://everywhen.me. And I don't know if I'd ever trust a score I hadn't reasoned myself. I already do a version of this style of rubberducking with LLMs and the idea score you naturally give something changes with each unexpected key question the LLM spits out. Problem is you don't know what key opens your idea or closes it and it needs to be worded just right.
Like "who is angered most if they could no longer get your product" and "under what context is the value your product provides most apparent to your target audience".