Okay, as a moderator here, I'd like to course-correct this thread a little and lay a few things out for future threads.
This topic is definitely something that's been talked about a lot before. It's okay to start a new thread that builds on those conversations; in fact, we'd rather people do that than resuming a long-idle thread. We want to make sure we're building on those past conversations, though, instead of repeating a lot of stuff that's been said before. The best way to do that is for the original poster (the "OP") to explicitly link and refer back to previous discussions.
If that hasn't happened, it's okay for other posters to refer the OP to some things they might want to read. This should always been done in a welcoming and constructive way, and that almost certainly means linking some of the proposals and/or threads you have in mind, as well as avoiding "moderator voice" or lecturing the OP about what they need to do. A simple post like "We talked a lot about this in the pitch for SE-0172" will usually do. Being welcoming and constructive is particularly important if the OP is a new user (which of course @tera is not), but it's expected regardless.
With that said, @tera, I think it would help to consider what your goal for this thread is. Your original post definitely reads like an early pitch for an alternative ranges design centered around a unified, currency range type, and you've been here long enough to know about our expectations around such threads. If this is meant to be a request to improve the docs, I think it would help to make it a clear and constructive suggestion. If it's just an unconstructive gripe about the API, I mean, I'm not sure we need that here.