As you can see, your six mana gives you a good sized, hard to answer on curve 7/6 dork with hard ward with sacrifices of legendary stuff only, like your Commander
When I see someone tap three Mountains and five other lands, I fear what may be coming
That said, it could be just enough to give you an edge over your opponents
When Sisu hits the board, your opponents lower-strength characters will be left turned to stone
Our inherent ignorance of traditional forms of grave hate and our lack of reliance on non-creature spells makes us extremely hard to interact with for most decks - and that, coupled with the sheer speed we can assemble the combo, has made us one of the most notorious decks in the cEDH metagame (along with mind-bendingly complex loops)
Even when a couple of them are great cards in their own right