Kaldheim brings with it new keywords such as Foretell, which allows you to exile cards from your hand to play them later for slightly cheaper, and Boast - which is a lot like the Raid mechanic from Tarkir, but this time around you can use special effects on cards for a different cost
You can quickly replicate an arsenal of equipment tokens with Arna, and since it triggers anytime a modified creature you control attacks, you can go wide with your creatures
Its also good against reactive control decks, making them discard their cards while you play your cheap threats
The card is no Elspeth, Suns Champion, but it might end up being the second-best white six
Think about your Commander decks
He is a quintessential Voltron commander, with the goal of eliminating players in just three hits of commander damage