A Digimon with 10% bond will transfer almost nothing during evolution, wasting all your stat-building efforts.Wrong Personality ChoicesUsing a Zealous personality (ATK/SPD focus) on a Digimon you want as a magical attacker severely limits their potential
Cards that are too expensive (7 or above), too hard to cast, or just don't make an impact on the board will generally go in one pile per color
While the weakness to aggro likely means it will never beat a Grand Prixwinning list, you can certainly post a good record with it on Magic Arena (where Mono-Blue Mill is also super cheap, at just 9 main-deck rares and zero mythics) or at your local Friday Night Magic
I'll run through the rest of the contenders here and talk about their pros and cons, but really it might all come down to the metagame you predict and the way you like to play the deck
This is more of a casual, themed deck, but with the right metagame and new supporting cards, it could be a competitor