The strategy is built around artifacts and counters, with a special focus on charge counters and the powerful proliferate mechanic
Specifically if you can meet them and see the cards in person and they allow you to verify its authenticity or provide you with authenticity verification paperwork
A quick glance on eBay shows a fair few for sale still, but in varying graded conditions
In blue Commander decks led by Tamiyo, Inquisitive Student or Emry, Lurker of the Loch, that control works perfectly since those decks usually just want time to set up their own game plan instead of dealing with every single threat directly
TCGPlayer: Trusted for US buyers, but the selection of Japanese promos may be limited
Similarly, it will take until Avatar: The Last Airbender is released for us to know whether this is a long-term trend