What almost everyone has brushed by is the fact that this will make measurements more accurate and the results fairer.
Measuring accurately the to the last full quarter inch is impossible. Heck getting HS judges not to measure to the last full quarter inch in the discus (it's supposed to be the last full inch) is nearly impossible.
This will also give kids, especially in the throws, a chance for more "barrier" PR's. 40 feet will still be a target for a beginner in the shot, but then so will 12 meters, and 13 meters, and 14 meters, and...
The only problem with this proposal is that it seems to mandate announcements only in m/cm. If the announcers and judges can announce the imperial conversions along with the metric measurements - which others have noted is mandated at NCAA meets - then this will be a clear improvement.