So long as it's on the battlefield, only one nonartifact spell can be cast
However, the ST16 has 9-cost Shanks, a control late-game Character that can be added to many Green decks like Bonney, Lim, or Smoker
Generally you do NOT want to overly hinder your own gameplan to cautiously hold up gale, especially against a good player who knows how to play around it
Yumas slower but more impactful token creation paired with all the cards it can draw works for a grindy, midrange-style deck while Hazezons more aggressive token production makes it better suited as an aggressive commander
However Box Toppers are not always foil cards and can sometimes be non-Foil
Although this is a combo archeype it is not a win on the spot kind so cards like Pact of Nagation (3.5) are fairly useless