No, it isn’t.

No, it is! It just wasn’t. It was initially based on something else but it now is exact.

The imperial units being a function of standard units is not enough. That is tedious conversion. And you seem to repeatedly emphasize its for “common people” and “everyday life”. If digferent units for same quantity isn’t a multiple of powers of 10, then the conversions are no mind calculation. This would alienate units of same quantity from each other.

The six feet thing is just a reference arised only because that unit was used. We could still use “about 160cm(or 16dm if you like) tall” or so to refer to an average person’s height.

I am not making claims on lack of precision of imperial system or so, but lack of consistancy in each of the units within the imperial system.

For scientific computing, its for convenience to see everything in powers of 10. Maybe not the computation itself but let’s say Planck’s constant in a totally different unit would look completely unknown if its not a change in factor of power of 10.

There is no reason to NOT use metric but… that is more just because most of the world uses metric.

And why is that? I think its because its much more consistant, well formed and simple enough that one can identify how long a kilometer is only by knowing how long a meter is.