A triggered ability automatically triggers when you meet a certain condition
You can also do things like swing as a creature with myriad, then transform into a more interesting creature that you actually want to copy, or you can use the counters to become versions of creatures with way more power than they ever expected
After all, its not easy to keep track of everything when a new product is released every 4.4 days on average
However, this comes at the small price of not being able to tribute it, or use it as a material for Fusion, Synchro, or XYZ summons
Reserved List buyouts and price increases have been parts of the Magic finance realm for years now
Once players have collected one of each of these Pokmon the 3 Star Mew card will unlock