While the Commander format does a good job of providing a soft landing spot for those who enjoy social play (albeit couched in a massive card pool), any players with an itch to try 60-card Constructed Magic with their new cards would have to go right to Modernwith over 20 years of card setsor Legacy, which is even bigger
Of course, getting up to the 14 loyalty needed to use this ability will be incredibly difficult without ways to speed up the process (such as proliferating yourself), or with a big enough army to protect Karn from attackers for the two turns needed to set him off
Artifacts are difficult to destroy, so it usually sticks on board, dissuading opponents from playing future threats
Plus, there's something nefarious going on in each land's art, a fun nod to the murder mystery flavor of this cross-over
Here are some great products I've found to do just that