Appreciate your comment and upvote! My understanding is that the difference between these NFTs and the tradtional L2 Hive NFTs is that these doesn't require centralized databases/smart contracts. The blogpost link below has more info from the creator of the solution, including a link to the API documentation. I'll tag @simplegame here as well, perhaps he'd like to provide further info.
https://inleo.io/@simplegame/stop-paying-minting-fees-darkcloaksio
Also feel free to check out the other info-clip I made the other day that sort of addresses your question too:
actually because they use Layer 1 JSON with human readable attributes and use the native tokens of the blockchain Hive/ HBD.
We can claim they are layer 1.
I have written many blog posts on this topic and my view point of it.
Now we have built a Layer 2 API infrastructure for game companies to use to interact with the Unity game engine for some of the intelligence that normally people think you need a smart contract for.
if you disagree and think smart contracts are the way to go. You might want to look at what VSC is building.