I don't really see how this helps any of us as end-users? Sure it will most likely result in someone figuring out that Apple is not doing what they claim to do so it makes it more difficult for Apple to say one thing but doing the opposite. But there are still no tools for me as an end-user to really know any of what Apple is doing here other than trusting their word and hope that if they are not true to their word someone else will figure it out and hold them accountable for it.
On macOS I will most likely be able to utilise terminal and activity monitor, or install third-party software to keep a track of things, and even block the scanning I suppose.
None of this really matters. The whole problem is how this is happening on-device, meaning that we as users lose control. When you scan on-device there is nothing stopping Apple from scanning whatever. Sure I do trust Apple as a company. But they are a public traded company, if markets like China, Russia, India starts putting pressure on Apple to utilise these on-device capabilities to scan for other material they will most likely be forced to comply.
Why would they create tools on-device like this. From a privacy perspective, it makes no sense and it opens a huge can of worms.