Both systems are broken. The British system is a bit more nominally consistent, but the names are poor; million and milliard are stupidly phonetically similar for what they are (generally we prefix those differences, probably because it's the ends of words that tend to get slurred, hence we have milli-meters and not meter-millis), and staggering the names out two chunks of 3 at a time doesn't really make much sense. It isn't very user-focused.

The American naming system uses roots more clearly and doesn't have the weird pointless bundling together of two groups of 3, but it has a bizarre off-by-one issue... and not the usual 0->1 or 1->0 issue, but a 1->2 issue. For consistency, the order ought to be "ones, millions, billions, trillions, quadrillions", so that the prefix on the digit counter indicates the number of factors of 1000 in question, from zero, one, bi=two, tri=three, etc. However, "thousands" get stuck in there wrecking the whole thing up, so where the names say you have 1 group of 1000, you in fact have two, and so on.

It's not an imperial vs. metric sort of thing, it's more an arguing which is the "real" temperature, Fahrenheit or Celsius, when in fact the answer is basically neither because the "real" temperature scale ought to have its 0 at absolute zero, like Kelvin [1] or the lesser-known Rankine [2], which is basically "Kelvin, except the degree is 1 degree Fahrenheit". These are both more "real" because now you can add and subtract temperatures meaningfully, which you can't do with either of Fahrenheit or Celsius. And likewise, neither number system is abstractly all that great. But then, that's part of why we have scientific notation.

[1]: Which I just learned is about to be redefined, as of May 20th, 2019: https://en.wikipedia.org/wiki/Kelvin#2019_redefinition

[2]: https://en.wikipedia.org/wiki/Rankine_scale