“maybe someone can ask Apple why the reference to Bitcode in Wednesday morning’s session vanished between Monday and Tuesday.”
I’m not Apple, but obvious potential reasons are that
① Bitcode is not yet reliable enough for commercially-released apps on the huge range (fragmented! 😋) iOS hardware base;
② Some oddball data-types, vector-instructions, etc., are handled poorly for some ARM targets, but these are not relevant on watch. (Variant on #1) Relatedly, that targeting is not yet robust.
③ Apple’s distribution infrastructure for iOS, which includes Company App Stores, iTunes servers in companies, iTunes on various platforms (including PCs?), etc., is not ready;
④ Apple’s developer infrastructure is not ready to test for possible compiler/linker bugs that might show up in Bitcode apps;
⑤ Once all the above *IS* ready for iOS, a developer will have essentially nothing to learn that requires a presentation session.
⑥ Apple’s legal staff only recently became aware of some weird intellectual property (patent) concerns that will affect selective downloads over the internet, in a way that wouldn’t apply to you compiling the app on your phone & installing on a watch. See FaceTime.
Well, it’s time to go home. I hope we’ll see this in 2015, and that it’ll be as cool as it has potential to be. But it is a lot more complex than we’d like it to be.