That's due to its sheer power - it's good enough that it sees play in the MtG Modern, Legacy, and Vintage eternal formats
This deck works well out of the box, but it is very dependent on its commander and includes some slightly odd cards that can be replaced with better options
Combo finish : Compact win conditions that use recursion or loops (e.g., Mikaeus )
I spent quite a bit of time delving deeper into the different approaches before I even started coding myself
Against the wrong deck, this can make it significantly less useful, however, thankfully in Commander, there are multiple opponents
Blacks Crystal offers some rather unique effects that could go in a variety of different decks, but unlike some of the other Crystals, this doesnt really create any exponential value