If flipping coins can work for Mistys Energy acceleration, then flipping a coin to get back an essential card you want to use again falls under the lines of Pokemon TCG other card standards
Card Types 200
The actual K9 package is fairly extensive, and what takes it from a Gamma/Driver handtrap package to a true second engine is 3 copies of K9-66a Jokul, helping us Summon Urubonus or our other K9s for free, and searching most often an Izuna once its on the board
It also grants ramping and enters-the-battlefield value, and the ability to take back stolen creatures
Both the angels and demon work with the graveyard: Reya resurrects creatures from my grave, Deathpact resurrects herself from my graveyard, and when an opponent's graveyard gets filled, Kothophed makes me lose a life but gain card advantage
Fixing colors also maximizes the power of Leyline Binding, a vital piece of interaction for the deck