Regarding use cases
ERC-721 and NFTs were designed, and are primarily used (in quantity of tokens and value of transactions), for healthcare, retail, in-game purchases and enterprise use cases. I am excluding one specific NFT token sale in this analysis until evidence can be provided it was not a shill sale.
Your proposal begin the discussion on security with “security - but I’m not exaclty [sic] sure how the non fungibles can have added security”.
This is not actionable advice.
My experience is that many people want to create applications without hiring developers, and publish standards without making applications. This is wholly backwards.
For example, this thread starts with the motivation that ERC-721 is “lacking security”. I consider this fake news given the above reference in the details.
Going forward, I recommend this could be addressed another way.
The concern “I find missing in both ERC721 and ERC1155 standards”… “no attached hash to the image / multimedia file itself as a proof” is better addressed by going to the Stack Exchange and asking “How do I attach the hash of a multimedia file to a ERC-721 or ERC-1155 token?”
The concern “missing downloadable standard which I define as more of a nice to have feature” is better addressed by creating a concrete token product, creating a good user experience, dealing with the practical considerations of building a thing (typically involving spending money and hiring people) and then making it work. Then after you have solved the problem, come back to the community and show off how well it worked, possibly as a standard.