Prices need to be informative, not necessary stable
Discussion
It's not about stability, it's about the effect of deflation on your consumer behavior. In deflation, you delay consumption and don't exchange deflationary currency in anticipation of its higher value in the future. If you have other nondeflationary money available, you are more likely to use that.
You have a great point, but I think it’s also fallacy. I’ve tried to express it here:
https://github.com/hynek-jina/Hynek/blob/main/blog/Is%20it%20time%20to%20pay%20with%20bitcoin.md
Or here in czech here: