The fact that he has Ward is actually quite ironic since most tables will likely leave Winter alive most of the time out of greed
Our commander is a planeswalker, which means he benefits from all our Superfriends support cards in a way that Breya/Atraxa cannot: we can activate him an extra time with The Chain Veil, he gets extra loyalty counters when we proliferate with Inexorable Tide, and he's a bonafide finisher when we resolve Obliterate
Thunder Magic and Dreams of Laguna, for instance, can fulfill URs condition despite having respective mana values of 1 and 2
Arguably even more important than that, however, is Sephiroths ability to counter the Broodscale combo matchup
1x Foil Card (random rarity)
With Zombify, however, you can discard a powerful legendary creature to Fear of Missing Out, Bitter Reunion, or Bitter Triumph and bring it back to life as early as turn four