At least Teferi, Ender of Friendships could be used, in theory, for something else, (even if no one actually does in real life.) Here, we all know what's about to happen
The last ability also cares about the first life gain you have during a turn, putting a +1/+1 counter on all your creatures
Horrific Symbiosis At the beginning of your end step, exile up to one target creature card from an opponent's graveyard
Electroduplicate Copying a creature like this is one of my favorite red effects because there are so many different things that you can do with it
Every set has its own theme and potential Commanders, and each of them has the potential to spike demand for existing cards.
Both these effects are solid on their own, but Stone Of Erech gets to have both effects on one card