> All the crap of AI / machine learning to prevent cross-site tracking that's useless to me in "Private Browsing" mode
Private Browsing, on its own, can only limit the scope of cross-site tracking to a single Private Browsing session. It does not prevent cross-site tracking within that session. (For example, if you visit two web sites within a Private Browsing session which both use Facebook widgets, Facebook may be able to correlate your activity across those sites.)
True, and a good point. I scoff at Webkit ITP because Apple has tried to "balance" the needs of the advertising industry vs Safari users. I prefer a more aggressive solution - prevent the tracking cookies in the first place. Take the example you cited - if uBlock Origin removes the Facebook widgets, and blocks Facebook tracking on all websites I visit, I won't have any tracking cookies in the first place. That automatically prevents cross-site tracking within a particular session. It must be obvious this solution is much more effective and hence why I consider ITP inferior.
Private Browsing, on its own, can only limit the scope of cross-site tracking to a single Private Browsing session. It does not prevent cross-site tracking within that session. (For example, if you visit two web sites within a Private Browsing session which both use Facebook widgets, Facebook may be able to correlate your activity across those sites.)