Apple’s modern programming language is easier to understand for non-iOS developers and minimizes time for additional explanations and clarifications. Moreover, Swift can be used as a script language. It is an interesting solution for the iOS community to unify writing of build scripts. At the time being iOS developers are split up in regard to this activity. Some of them write build scripts in Bash, others use Ruby, Python, etc. Swift gives an amazing opportunity to be applied to all iOS programming needs.
More details can be found here https://mlsdev.com/blog/51-7-advantages-of-using-swift-over-objective-c
They've released 1.2 so far, and 2.0 is coming soon. Every small update brings adjustments to paradigms (such as how to do type casting) that can be a little frustrating to absorb. Objective C was also constantly updating, however, but not at the same rate these days.
There's nothing you can do in Objective-C that you can't do better in Swift. The only reason Objective-C is still around is that not everything has been ported to Swift yet. Yes, Swift is still evolving and you'll need to keep learning it each year, but it will stabilize and is absolutely the better language.
It will take a while for everything to move to Swift, and in the meantime, there's a lot of legacy code out there. You will need to know Swift, but a developer who ALSO knows Objective-C will get hired every time over a developer who only knows Swift