43 found a nice usage of mana inside my blue/green deck. It allows me to use 4 mana to get a basic land out of the deck into my hand.
It doesn't sound like much but I can repeat it as long as I have mana and my commander makes it so I have no maximum hand size AND allows me to bring left over mana to my next turns. Or in other words, it allows me to reasonably quickly get a good chunk of lands out of my deck to make the chance on drawing good cards MUCH better.