Metric measurement cannot be taught in less in a minute. All you have done is instructed people in are multiples of ten, not measurement All units of measurement are based on a standard like imperial measurements "body parts" as long as it was an exacting standard that could be replicated it is acceptable. The imperial "mile" (a pronunciation of milli) IS a metric measurement. It is based off 1000 paces as performed by a roman legion. Since it was a roman legion you could darn sure it could be replicated EVERY time.
And which meter/metre are we talking about here then? The original measurement base of one ten-millionth of the distance from the equator to the north pole? (Not the south pole mind you) The meter/metre that was MADE UP by the Metre Convention of bar composed of 90% platinum 10% iridium measured at the melting point of ice? How about the krypton standard bulbs basis on wavelength? Or finally, the modern day meter which uses the speed of light traveled in vacuum in 1/299,781,458 of a second. Aside from the first none of these example measurements are metrically based on multiples of ten.
How will I apply these measurements in-game? Is it truly easier to say fly in 'such in such' direction for 149.6 million kilometers because it's metric or will I give a standard unit of measurement of 1 AU which is the same distance and much easier to comprehend?
Measuring or utilizing speed or distance will never be as simple as saying "use metric".