To the extent that this allows me to reconnect and get a work out in with old friends - and possibily interests some new folks - this is a good thing. If I can, I'll join one of the events.
That is why I like our Taoist Tai Chi awareness day, as you have like a 1000 people all doing the same exact Tai Chi set. It's very powerfull when you have that many people doing the exact same thing. A world Tai Chi day is a good idea but wouldn't be as organized... perhaps that is why we do our own day.
What constitutes "impressive" is ultimately a subjective matter.