Dartz's theme is extremely specific (Orichalchos), and we already have Shunoros, and it's a crap card. Geh is still too broken for DL. So that left us with just The Seal. Not enough for a character's level up reward and drops, unless they want to give us all those crap anime-only cards. Mirror Knight Calling couldn't even be in DL since it summons 4 Tokens, thus requiring 5 zones to play it.
And what about Dartz's level 40 deck when he's at the Gate? His deck would be an inconsistent mess that doesn't do him justice, it really only works in the anime.
As for Noah....what would he even give us as drops and level up rewards? We already have all of the cards related to him.
Sartorius is a different case, he has cards to give and the rest of the lines is a pre-emptive measure just in case the real life game randomly decides to completes the set one day.
Problem is, that most of his cards haven't been released yet or are very different than they were in the Anime. Just take a look at Orichalcos Shunoros:
https://yugioh.fandom.com/wiki/Orichalcos_Shunoros
Anoymous
Zerodx
