RGB started as some coloured coin stuff on top of Bitcoin but then evolved to be a complete smart contacting solution. What makes it different is that it uses a mechanism called client side validation where the wallets and other client software are responsible for making sure the txns are valid and only some minimal data is put on chain. The team then took that same idea to propose a blockchain design that'll only have the block header and all the actual data will be stored in parts by nodes that actually need that data. I think it's an interesting design, even though I don't think creating a new coin is the answer to anything