I was (pleasantly) surprised to see that the analogous website for Mexico, where you buy government-issued bonds called Cetes, is significantly less confusing to use. That is not at all what I expect when comparing government websites between my native Mexico and the US! (Paying taxes is another example of something with much, much better UI/UX in Mexico, but there probably are not many other examples.)

Also, the refunds for Cetes when you go over the limit take a few days, not 8 to 10 weeks.