My car has a little screen in the dash where it usually shows my range, or the current temperature - information that I check when safe to do so, but never very urgently. This is the perfect place for a warning about low wiper fluid.
As for forward collision warnings, ehhhh. Maybe that should beep loudly, but it should almost never be wrong! (A false alarm could easily mean I slam on the brakes and get rear-ended, so that has to be balanced with the safety advantage of the true alarm.)