Whatever format you play in Magic, there were multiple cards released that you can play with and upgrade your decks with (or, in some cases, these cards wound up creating entirely new decks)
I don't think that at this very moment, if Yuriko didn't exist, there would be a very strong case to argue that this is the best in class for a ninja-themed deck
The downside is that since you have to attack with Varragoth, you have very little agency over what it trades for, but that seems like a fair trade-off for a free Vampiric Tutor
And therein lies the rub
The Mox: Emerald, Jet, Pearl, Ruby, Sapphire Add 1 [color] mana to your mana pool
The table it simulates has no built-in rules, so players are mostly tapping and drawing and searching for cards manually