This is huuuuge. I don’t see announcement of 3rd party training support yet, but I imagine/hope it’s planned.
One of the hard things about local+private ML is I don’t want every app I download to need GBs of weights, and don’t want a delay when I open a new app and all the memory swap happens. As an app developer I want the best model that runs on each HW model, not one lowest common denominator model for slowest HW I support. Apple has the chance to make this smooth: great models tuned to each chip, adapters for each use case, new use cases only have a few MB of weights (for a set of current base models), and base models can get better over time (new HW and improved models). Basically app thinning for models.
Even if the base models aren’t SOTA to start, the developer experience is great and they can iterate.
Server side is so much easier, but look forward to local+private taking over for a lot of use cases.