Now that previews are officially underway, we can finally show you
This is represented within the text box of the Aura card
The trick is to sacrifice a few treasure tokens, then spend the floating mana to cast a cheap Balrog
People like to buy boxes to crack lots of packs, have higher chances of finding that special rare or mythic they need, or play Limited
While abilities like hexproof, ward, and shroud can provide defense from spells, flying allows a creature to avoid blockers without flying or reach, and strike a player directly
BPhillipYork: I mean, it's a planeswalk card so it's only relevant if you are actually using planeswalking which seems pretty rare, if you are it's a decent mana dork in the Command Zone and lets you really leverage that planeswalking