RGB in theory is very interesting. As a super-simplified example, its a way to add extra-data to BTC transactions to enable things like: Assets, Privacy Coins, Smart Contracts, etc....

This works because it moves all those fancy features off to the client to deal with. So if you have a non-compliant wallet / node, it just ignores that extra data. Naturally, because its just bitcoin, these additions can also function over LN.

This is very elegant since it will have no impact on existing network....you can just safely ignore all that stuff and only people with RGB-enabled wallets will see them.

Taro of course is proposing something really similar.....in fact so similar that there have been claims that Taro simply copied most of RGB.....

I don't know enough of the details to weigh into that, but its interesting seeing that Blockstream is get closer to RGB. Clearly they are choosing a side....