The final cut of the 8th episode of the Tesla Motors Club Podcast, featuring Balazs Biro, of the prominent Hungarian EV channel Villanyautósok, is now available. You can watch it now on YouTube or listen to it on all major podcast networks.
The B pillar cameras until recently were only used for FSD features - probably auto lane change and latterly smart summon. Nothing official, but that does now appear to have changed, at least in part as all external cameras now seem to be inputs into the fusion layer which may or may not be being used by additional features.
Tesla Cameras' Coverage and Field-of-View for AP is a great thread showing camera capabilities - post 8 will answer part of your question. Subsequent to this, FSD beta testing videos show its capabilities it in real world use - not perfect in some situations but Tesla seem to be coming up with work arounds such as car creeping at junctions to get a better view.
Internal camera was enabled (with driver permission) in one of the releases in latter part of last year - cannot remember which one exactly but it was in the release notes. Tesla are using the data for learning about driver awareness, hopefully as an alternative to the steering wheel nag.