How does CDP backup work? Is it an effective replacement for traditional backup solutions?
No it does not replace backup. This supports RTOs in the case of DR, but backup establishes long term retention and separation for ransomware.
CDP is a significantly effective mechanism for protecting data, it is used for the highest priority environments or critical for business operations. For environments with a high RTO.
The backup platform being used could have CDP (continuous data protection) as an integral part of the solution. It is the first stage of user data back up, this gets added to the main back up. So in summary CDP is part of back up when considering user data.