According to the Ring Confidential Transactions research paper of Monero (Link to the paper), in section 1.5. Ring Confidential Transactions Overview, it is mentioned:
"We describe a modification to the Monero protocol, a proof-of-work cryptocurrency extending the original CryptoNote protocol. The modification is based on Confidential Transactions which are used on the Elements side-chain in Bitcoin, except it allows for their use in ring signatures [cited to this article as reference]. Therefore, the modification is given the obvious name of Ring Confidential Transactions (Ring CT) for Monero."
However, in the cited article (Link), it is mentioned that the Ring signature is used in Confidential Transactions of Bitcoin too.
If so, why in Monero's paper it is mentioned that "except it allows for their use in ring signatures" as its difference with Bitcoin Confidential Transactions ?
Is "Ring Confidential Transactions" used in both Bitcoin and Monero?