I think an Egon / Throne of Death plan will make it easier to keep Egon around, but there are easier ways to self-mill in Black without jumping through all those hoops
These are called unique abilities
Instead, it's the fact that it allows the player to draw two cards when an equipped creature dies that pushes it over the top The potential card advantage is unreasonable for a single mana investment, especially since the -1 to Toughness makes it extremely easy for the player to kill their own creatures on command
The Tenth Doctor (Serialized) - $1500 Surprise
You can cast a card with disguise face-down for mana at any time you could normally cast a creature spell
The mono-color identity, themes, commanders, and marketing all point towards simple, straightforward decks meant to lower the barrier of entry to the game rather than satisfy a desire for complex gameplay or new themes you might expect from a traditional precon