Only if the client-side scanning includes end-to-end encryption, which was never part of the deal. It was a possible future feature. Also, only if the-client side scanning only scans images being uploaded to iCloud and not literally everything.
Also any kind of content scanning is always strictly worse than no scanning at all.
One thing that was slightly confusing in the initial announcement was that it was said to be released on a day when no OS update was happening[0]. I've been unable to find details of how the rollout was supposed to happen, but if no OS update was needed the code would have had to already be deployed in a previous update before it was officially disclosed by Apple, wouldn't it? I don't know of any sources that show it was present and if so whether it has been verified that it was removed, but if such sources exist I would appreciate references.
EDIT: This announcement from Apple says it was to be included in an iOS 15 update when ready [1] so unlikely it was just dormant in some previous update.