>>I would use miles as units for that size tidal wave. It would eliminate confusion in reporting as zeros, houses, cattle, and coastlines are lost in the urgency of the moment. 1/2 mile. That's where the metric system comes up short: 'Did he say millimeters or kilometers?'<<
Yep, good for visuals... but metrics (and the subset called SI units) sure do make math easier.
Metric makes mistakes easier. I have never noticed that metric makes arithmetic easier. I have noticed that it makes not a bit of difference for practical purposes.