To have sample code for every new feature, etc. This should not be a coop or someone doing it in hindsight - the number of hours people spend re-inventing how to do infinite scrolling tableviews (one simple example) is sad - every new developer has to re-invent the wheel it seems.
This leads to people using third party libraries for things that need no libraries at all, and then before you know it, you're swimming in cocoapod soup, every time you join a new project, and the soup is 50% new ingredients every other time too!
I’m pretty sure they have multiple people with a role like this (I know they have one at least, since I’ve met him).
Nothing should break?
I’d argue the second option is almost universally better.
The last two years or so have been fine for me.
Steve Troughton-Smith, Michael Lauer, Dan Leivers, Peter Molnar, Todd Thomas, Ian McDowell, Simon Wolf, Marco Arment all didn't seem (2017-10-04) in a particular hurry to adopt Swift. 
The following quote from Steve Troughton-Smith in the article that I linked was enough for me - I'm not going to beta test Swift for Apple either.
>I'm not yet convinced of Apple's level of participation in the language — four years on, Swift is not used for important pieces of iOS, OS or frameworks (I maintain a running list of Swift apps from Apple on Twitter, and macOS is definitely less shy about adopting it for new features than iOS). I understand why that is the case (ABI stability, etc), but if Apple's not using it for everything I don't see why I need to be beta-testing on their behalf. I lose nothing from waiting until Swift is 'ready', and I gain all the benefits of Objective-C in the meantime.
$ otool -L `which launchd`
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.50.4)
/usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0)
/usr/lib/libauditd.0.dylib (compatibility version 1.0.0, current version 1.0.0)
/usr/lib/libbsm.0.dylib (compatibility version 1.0.0, current version 1.0.0)
/usr/lib/libdz.dylib (compatibility version 1.0.0, current version 110.50.29)
I guess we can go through the videos to track down where it was communicated.
You might want to check the username on that comment ;)