I think whether you use adrs or comments or git messages or readmes or whatever, the fundamental rule is simple: In any case where you're making a non-default

I think whether you use adrs or comments or git messages or readmes or whatever, the fundamental rule is simple: In any case where you're making a non-default choice in software, it needs to be explained in an easily-discoverable place so a developer that's looking at the project and trying to understand the why of something can see it. Too often I block PRs with confusing code and ask why it was done this way and the developer swings by my office or gets defensive and I have to say "no, I'm not attacking your code as being wrong, and I don't want a verbal explanation as to how it works. I want the decisions that led you to do it this way to be documented". ... But actually usually the code is just wrong.