The latest updates to the GitHub draft lay out a radically different structure, with ERC7583 defining a type of contract that is a (true) ERC20 and (renamed/tweaked) ERC721 contract at once. That hybrid blend of non-fungible and fungible token is something that non-inscription communities have been exploring lately and ERC7631 has come from that. ERC7631 seems to be pursuing the same goals as this updated ERC7583, in that users have their fungible tokens saved as discrete “bundles” of arbitrary value. The key difference is ERC7631 has the non-fungible “bundles” be true ERC721s. A significant downside of this updated ERC7583 is that the non-fungible part looks similar to ERC721s, but isn’t actually, and could confuse or break interfaces that assume they are.
ERC7583 having part of the contract’s state be accessible to other smart contracts (ERC20 interface) and the other part inaccessible (by attempting to save it as “an inscription”) seems like it’s significantly less useful. So, my opinion is that if a project wants the functionality of having a set of non-fungible tokens that “store” fungible token values for a user, we should help standardize ERC7631 as an interface to do that, to have the best compatibility with all other smart contracts in the space.