Really you find mmol/mol easier to understand than %?
I think most lay people would think otherwise.
Also seldom do we refer to the units when talking about these levels. And because we are really looking at the trend of the levels it doesn't really matter which units you use.
It's a bit like saying oh my time for running the 100m is 15s vs 0.25 minutes or 0.004166h 5 years ago and now with training I am down to 0.16 minutes.
And then say oh we are moving away from using seconds to count the 100m times and using minutes.
no I think that lay people tend to understand % better instead of esoteric units, but I don't think it really matters in the end....
with just about everything, eventually users develop a framework of familiarity. sam mentions this about feet inches vs metric. I used to think of plasma glucose only in mg/dl. now it only makes sense in mmol/l.
and because I spent so much time in NA, if you tell me a car is 190 inches long I have a good idea whether I want to have it. If you tell me 4826mm, I'm in trouble.
Actually, talking about this brings up some thoughts.
The metric system as wonderful as it is for calculations is derived from esoteric phenomena whose bases is typically unobservable for the average Joe or Ah Seng.
the metre is some fraction of the distrance travelled at the speed of light in a second. the kg is even worse, derived from the Planck constant used for calculating EM energy on the basis that energy and matter interchangeable. liddat how?
imperial units fare far better for making common sense. everybody got foot can easily see the connection. even if the unit makes no sense, it is at least easy to quantify. go drinking can easily ask for 1 pint. metric is 47x ml or perhaps half a litre.
so in the end, the North Americans kind of have the best of both worlds. daily use measurements in imperial, scientific and engineering calcs in metric.