What is colored coin in layman terms?

[r1s2g3]

Recently I come across the concept of colored coin.

https://bitcointalk.org/index.php?topic=347398.0

It says some extra metadata is put in bitcoin blockchain to make it colored. That extra metadata always associated so that it will always be identified.

1. How this extra metadata is introduced?
2. Is it really a useful concept?

[AdolfinWolf]

Recently I come across the concept of colored coin.

https://bitcointalk.org/index.php?topic=347398.0

It says some extra metadata is put in bitcoin blockchain to make it colored. That extra metadata always associated so that it will always be identified.

1. How this extra metadata is introduced?
2. Is it really a useful concept?

There have been some other threads about this; Might be worth reading.

https://bitcointalk.org/index.php?topic=214316.0


And:
https://bitcointalk.org/index.php?topic=106373.0

By the original design bitcoins are fungible, acting as a neutral medium of exchange. However, by carefully tracking the origin of a given bitcoin, it is possible to “color” a set of coins to distinguish it from the rest. These coins can then have special properties supported by either an issuing agent or a Schelling point, and have value independent of the face value of the underlying bitcoins. Such colored bitcoins can be used for alternative currencies, commodity certificates, smart property, and other financial instruments such as stocks and bonds.

https://github.com/bitcoinx/colored-coin-tools/wiki/colored_coins_intro

Would something like this still work? How exactly do i broadcast this? Using the testnet? Do i need a "color-aware" wallet? -- https://github.com/Colored-Coins/cc-transaction-builder
Do those wallets even exist still?

The entire implementation looks rather depreciated?

2. Is it really a useful concept?

It seems like it could be very useful, if implemented correctly, as explained above, but i haven't seen any projects apart from USDT (or XCPaccording to [1]) worth noting that use(d) colored coins. Perhaps because there are better and easier alternatives available. (such as ERC20?)
[1] https://bitcointalk.org/index.php?topic=5004218.msg45203731#msg45203731

[r1s2g3]

Thanks for sharing the links.
Concept is old but does not look popular. I assume it do not have practical usefulness after ETH come into picture with capability of creating tokens.