Rules and Errata

The Blackjack boons from the Blackjack Role in the CotCT Sanctioning document provides multiple weapon and item deck upgrade options automatically (as you shuffle 3 level 3 cards into your deck at the start of a scenario), which is almost certainly not the intent. Note that almost identical wording was used in the Tyrant of the Harrow reward to intentionally provide players with new Blessing upgrades, cementing the RAW interpretation.