After having launched Simple Assets, CryptoLions recently added also Non-Transferable Tokens (NTTs) into their digital assets standard. Simple Assets is a standard for digital assets, both fungible and non-fungible tokens, for EOSIO blockchains. NTTs will be mainly used as give awards and trophies or official certificates and licenses.
By using a digital asset standard as such, developers won't need to build all asset logic from scratch, saving hundreds of hours of work. In addition, it will be easier for third-party projects (eg. explorers) to retrieve the same assets saved in the blockchain, allowing for greater utility.
"We think that making NFTs sometimes transferable and sometimes not, muddles the pure expression of ownership which we strive to achieve with Simple Asset NFTs. NTTs are a distinct form type of property, operating under different rules, and deserve their own vocabulary."