SI units are the International System of Units. Basically after WWII, the science community got tired of all the different systems of measurement, including different nations using different metric systems. So, they consolidated everything so that moles, meters, degrees K, etc all meant the same thing for everybody.
Just because someone calls something “international” doesn’t necessarily make it so. In the USA, it’s called the metric system.
And frankly, the bar is not “SI”; it’s actually considered deprecated by those scientists.
Back in the 1970’s, when President Carter was trying to get us to adopt the metric system, Chicago Tribune columnist Bob Greene started a movement called We Ain’t Metric. “Why won’t we adopt the metric system?” he asked—”beacause we don’t like it. Why won’t we cooperate with the federal government’s efforts to get us to use it? Because we don’t want to.”
I was, and am in full agreement.