You can buy outfits and other unlocks with creds, but creds are only available as a random drop, or you get 1/5th the value of a drop if you have it already. Moreover, event items have their cost tripled, but their value for duplicate creds isn'tCaramel Frappe said:The trailer was just so ... jolly and in the spirits of Christmas, I may have to pick up Overwatch again just for Christmas's theme. However I still feel upset about Blizzard's business practices with the loot system (though some have told me you can simply pay now for certain skins that you desire so, maybe my interests will spark anew).
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Additionally, they stop being cred buyable as soon as the event ends