Which is why I'm discussing this, too: What Should be Banned But Isn't
This not only allows your deck to have access to additional colors but also helps get around the command tax since each of your commanders gets its own command tax, helping ensure you always have something to play from the command zone if you have nothing better to do
The more you help one friend, the more you annoy the other
Likewise, it also works really well in counters decks (like my Hamza, Guardian of Arashin deck), as the cost to prevent your draw will increase as Esper Sentinel gets bigger and bigger, easily making it more costly to pay for than even Rhystic Study
I've watched Peter Parker go through trials and tribulations, reach the heights of personal success, and then go back to square one many, many times